ToolStripItem 类

定义

public ref class ToolStripItem abstract : System::ComponentModel::Component, IDisposable, System::Windows::Forms::IDropTarget

public ref class ToolStripItem abstract : System::Windows::Forms::BindableComponent, IDisposable, System::Windows::Forms::IDropTarget

public abstract class ToolStripItem : System.ComponentModel.Component, IDisposable, System.Windows.Forms.IDropTarget

public abstract class ToolStripItem : System.Windows.Forms.BindableComponent, IDisposable, System.Windows.Forms.IDropTarget

type ToolStripItem = class
    inherit Component
    interface IDropTarget
    interface IComponent
    interface IDisposable

type ToolStripItem = class
    inherit BindableComponent
    interface IDropTarget
    interface IComponent
    interface IDisposable

Public MustInherit Class ToolStripItem
Inherits Component
Implements IDisposable, IDropTarget

Public MustInherit Class ToolStripItem
Inherits BindableComponent
Implements IDisposable, IDropTarget

继承

Object

MarshalByRefObject

Component

ToolStripItem

继承

Object

MarshalByRefObject

Component

BindableComponent

ToolStripItem

派生

System.Windows.Forms.ToolStripButton

System.Windows.Forms.ToolStripControlHost

System.Windows.Forms.ToolStripDropDownItem

System.Windows.Forms.ToolStripLabel

System.Windows.Forms.ToolStripSeparator

实现

IComponent IDisposable IDropTarget

示例

下面的代码示例演示如何实现自定义 ToolStripItem 控件。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace RolloverItemDemoLib
{
    // This class implements a ToolStripItem that highlights
    // its border and text when the mouse enters its
    // client rectangle. It has a clickable state which is
    // exposed through the Clicked property and displayed
    // by highlighting or graying out the item's image. 
    public class RolloverItem : ToolStripItem
    {
        private bool clickedValue = false;
        private bool rolloverValue = false;

        private Rectangle imageRect;
        private Rectangle textRect;

        // For brevity, this implementation limits the possible 
        // TextDirection values to ToolStripTextDirection.Horizontal. 
        public override ToolStripTextDirection TextDirection
        {
            get
            {
                return base.TextDirection;
            }
            set
            {
                if (value == ToolStripTextDirection.Horizontal)
                {
                    base.TextDirection = value;
                }
                else
                {
                    throw new ArgumentException(
                        "RolloverItem supports only horizontal text.");
                }
            }
        }

        // For brevity, this implementation limits the possible 
        // TextImageRelation values to ImageBeforeText and TextBeforeImage. 
        public new TextImageRelation TextImageRelation
        {
            get
            {
                return base.TextImageRelation;
            }

            set
            {
                if (value == TextImageRelation.ImageBeforeText || 
                    value == TextImageRelation.TextBeforeImage)
                {
                    base.TextImageRelation = value;
                }
                else
                {
                    throw new ArgumentException(
                        "Unsupported TextImageRelation value.");
                }
            }
        }
        
        // This property returns true if the mouse is 
        // inside the client rectangle.
        public bool Rollover
        {
            get
            {
                return this.rolloverValue;
            }   
        }

        // This property returns true if the item 
        // has been toggled into the clicked state.
        // Clicking again toggles it to the 
        // unclicked state.
        public bool Clicked
        {
            get
            {
                return this.clickedValue;
            }
        }

        // The method defines the behavior of the Click event.
        // It simply toggles the state of the clickedValue field.
        protected override void OnClick(EventArgs e)
        {
            base.OnClick(e);

            this.clickedValue ^= true;
        }

        // The method defines the behavior of the DoubleClick 
        // event. It shows a MessageBox with the item's text.
        protected override void OnDoubleClick(EventArgs e)
        {
            base.OnDoubleClick(e);

            string msg = String.Format("Item: {0}", this.Text);

            MessageBox.Show(msg);
        }

        // This method defines the behavior of the MouseEnter event.
        // It sets the state of the rolloverValue field to true and
        // tells the control to repaint.
        protected override void OnMouseEnter(EventArgs e)
        {
            base.OnMouseEnter(e);

            this.rolloverValue = true;

            this.Invalidate();
        }

        // This method defines the behavior of the MouseLeave event.
        // It sets the state of the rolloverValue field to false and
        // tells the control to repaint.
        protected override void OnMouseLeave(EventArgs e)
        {
            base.OnMouseLeave(e);

            this.rolloverValue = false;

            this.Invalidate();
        }

        // This method defines the painting behavior of the control.
        // It performs the following operations:
        //
        // Computes the layout of the item's image and text.
        // Draws the item's background image.
        // Draws the item's image.
        // Draws the item's text.
        //
        // Drawing operations are implemented in the 
        // RolloverItemRenderer class.
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);

            if (this.Owner != null)
            {
                // Find the dimensions of the image and the text 
                // areas of the item. 
                this.ComputeImageAndTextLayout();

                // Draw the background. This includes drawing a highlighted 
                // border when the mouse is in the client area.
                ToolStripItemRenderEventArgs ea = new ToolStripItemRenderEventArgs(
                     e.Graphics,
                     this);
                this.Owner.Renderer.DrawItemBackground(ea);

                // Draw the item's image. 
                ToolStripItemImageRenderEventArgs irea =
                    new ToolStripItemImageRenderEventArgs(
                    e.Graphics,
                    this,
                    imageRect );
                this.Owner.Renderer.DrawItemImage(irea);

                // If the item is on a drop-down, give its
                // text a different highlighted color.
                Color highlightColor = 
                    this.IsOnDropDown ?
                    Color.Salmon : SystemColors.ControlLightLight;

                // Draw the text, and highlight it if the 
                // the rollover state is true.
                ToolStripItemTextRenderEventArgs rea =
                    new ToolStripItemTextRenderEventArgs(
                    e.Graphics,
                    this,
                    base.Text,
                    textRect,
                    this.rolloverValue ? highlightColor : base.ForeColor,
                    base.Font,
                    base.TextAlign);
                this.Owner.Renderer.DrawItemText(rea);
            }
        }

        // This utility method computes the layout of the 
        // RolloverItem control's image area and the text area.
        // For brevity, only the following settings are 
        // supported:
        //
        // ToolStripTextDirection.Horizontal
        // TextImageRelation.ImageBeforeText 
        // TextImageRelation.ImageBeforeText
        // 
        // It would not be difficult to support vertical text
        // directions and other image/text relationships.
        private void ComputeImageAndTextLayout()
        {
            Rectangle cr = base.ContentRectangle;
            Image img = base.Owner.ImageList.Images[base.ImageKey];

            // Compute the center of the item's ContentRectangle.
            int centerY = (cr.Height - img.Height) / 2;

            // Find the dimensions of the image and the text 
            // areas of the item. The text occupies the space 
            // not filled by the image. 
            if (base.TextImageRelation == TextImageRelation.ImageBeforeText &&
                base.TextDirection == ToolStripTextDirection.Horizontal)
            {
                imageRect = new Rectangle(
                    base.ContentRectangle.Left,
                    centerY,
                    base.Image.Width,
                    base.Image.Height);

                textRect = new Rectangle(
                    imageRect.Width,
                    base.ContentRectangle.Top,
                    base.ContentRectangle.Width - imageRect.Width,
                    base.ContentRectangle.Height);
            }
            else if (base.TextImageRelation == TextImageRelation.TextBeforeImage &&
                     base.TextDirection == ToolStripTextDirection.Horizontal)
            {
                imageRect = new Rectangle(
                    base.ContentRectangle.Right - base.Image.Width,
                    centerY,
                    base.Image.Width,
                    base.Image.Height);

                textRect = new Rectangle(
                    base.ContentRectangle.Left,
                    base.ContentRectangle.Top,
                    imageRect.X,
                    base.ContentRectangle.Bottom);
            }
        }
    }

    #region RolloverItemRenderer

    // This is the custom renderer for the RolloverItem control.
    // It draws a border around the item when the mouse is
    // in the item's client area. It also draws the item's image
    // in an inactive state (grayed out) until the user clicks
    // the item to toggle its "clicked" state.
    internal class RolloverItemRenderer : ToolStripSystemRenderer
    {
        protected override void OnRenderItemImage(
            ToolStripItemImageRenderEventArgs e)
        {
            base.OnRenderItemImage(e);

            RolloverItem item = e.Item as RolloverItem;

            // If the ToolSTripItem is of type RolloverItem, 
            // perform custom rendering for the image.
            if (item != null)
            {
                if (item.Clicked)
                {
                    // The item is in the clicked state, so 
                    // draw the image as usual.
                    e.Graphics.DrawImage(
                        e.Image,
                        e.ImageRectangle.X,
                        e.ImageRectangle.Y);
                }
                else
                {
                    // In the unclicked state, gray out the image.
                    ControlPaint.DrawImageDisabled(
                        e.Graphics,
                        e.Image,
                        e.ImageRectangle.X,
                        e.ImageRectangle.Y,
                        item.BackColor);
                }
            }
        }

        // This method defines the behavior for rendering the
        // background of a ToolStripItem. If the item is a
        // RolloverItem, it paints the item's BackgroundImage 
        // centered in the client area. If the mouse is in the 
        // item's client area, a border is drawn around it.
        // If the item is on a drop-down or if it is on the
        // overflow, a gradient is painted in the background.
        protected override void OnRenderItemBackground(
            ToolStripItemRenderEventArgs e)
        {
            base.OnRenderItemBackground(e);

            RolloverItem item = e.Item as RolloverItem;

            // If the ToolSTripItem is of type RolloverItem, 
            // perform custom rendering for the background.
            if (item != null)
            {
                if (item.Placement == ToolStripItemPlacement.Overflow ||
                    item.IsOnDropDown)
                {
                    using (LinearGradientBrush b = new LinearGradientBrush(
                        item.ContentRectangle,
                        Color.Salmon,
                        Color.DarkRed,
                        0f,
                        false))
                    {
                        e.Graphics.FillRectangle(b, item.ContentRectangle);
                    }
                }

                // The RolloverItem control only supports 
                // the ImageLayout.Center setting for the
                // BackgroundImage property.
                if (item.BackgroundImageLayout == ImageLayout.Center)
                {
                    // Get references to the item's ContentRectangle
                    // and BackgroundImage, for convenience.
                    Rectangle cr = item.ContentRectangle;
                    Image bgi = item.BackgroundImage;

                    // Compute the center of the item's ContentRectangle.
                    int centerX = (cr.Width - bgi.Width) / 2;
                    int centerY = (cr.Height - bgi.Height) / 2;

                    // If the item is selected, draw the background
                    // image as usual. Otherwise, draw it as disabled.
                    if (item.Selected)
                    {
                        e.Graphics.DrawImage(bgi, centerX, centerY);
                    }
                    else
                    {
                        ControlPaint.DrawImageDisabled(
                                e.Graphics,
                                bgi,
                                centerX,
                                centerY,
                                item.BackColor);
                    }
                }

                // If the item is in the rollover state, 
                // draw a border around it.
                if (item.Rollover)
                {
                    ControlPaint.DrawFocusRectangle(
                        e.Graphics,
                        item.ContentRectangle);
                }
            }
        }

    #endregion

    }

    // This form tests various features of the RolloverItem
    // control. RolloverItem conrols are created and added
    // to the form's ToolStrip. They are also created and 
    // added to a button's ContextMenuStrip. The behavior
    // of the RolloverItem control differs depending on 
    // the type of parent control.
    public class RolloverItemTestForm : Form
    {
        private System.Windows.Forms.ToolStrip toolStrip1;
        private System.Windows.Forms.Button button1;

        private string infoIconKey = "Information icon";
        private string handIconKey = "Hand icon";
        private string exclIconKey = "Exclamation icon";
        private string questionIconKey = "Question icon";
        private string warningIconKey = "Warning icon ";

        private System.ComponentModel.IContainer components = null;

        public RolloverItemTestForm()
        {
            InitializeComponent();

            // Set up the form's ToolStrip control.
            InitializeToolStrip();

            // Set up the ContextMenuStrip for the button.
            InitializeContextMenu();
        }

        // This utility method initializes the ToolStrip control's 
        // image list. For convenience, icons from the SystemIcons 
        // class are used for this demonstration, but any images
        // could be used.
        private void InitializeImageList(ToolStrip ts)
        {
            if (ts.ImageList == null)
            {
                ts.ImageList = new ImageList();
                ts.ImageList.ImageSize = SystemIcons.Exclamation.Size;

                ts.ImageList.Images.Add(
                    this.infoIconKey,
                    SystemIcons.Information);

                ts.ImageList.Images.Add(
                    this.handIconKey,
                    SystemIcons.Hand);

                ts.ImageList.Images.Add(
                    this.exclIconKey,
                    SystemIcons.Exclamation);

                ts.ImageList.Images.Add(
                    this.questionIconKey,
                    SystemIcons.Question);

                ts.ImageList.Images.Add(
                    this.warningIconKey,
                    SystemIcons.Warning);
            }
        }

        private void InitializeToolStrip()
        {
            this.InitializeImageList(this.toolStrip1);

            this.toolStrip1.Renderer = new RolloverItemRenderer();

            RolloverItem item = this.CreateRolloverItem(
                this.toolStrip1,
                "RolloverItem on ToolStrip",
                this.Font,
                infoIconKey,
                TextImageRelation.ImageBeforeText,
                exclIconKey);

            this.toolStrip1.Items.Add(item);

            item = this.CreateRolloverItem(
                this.toolStrip1,
                "RolloverItem on ToolStrip",
                this.Font,
                infoIconKey,
                TextImageRelation.ImageBeforeText,
                exclIconKey);

            this.toolStrip1.Items.Add(item);
        }

        private void InitializeContextMenu()
        {
            Font f = new System.Drawing.Font(
                "Arial",
                18f,
                FontStyle.Bold);

            ContextMenuStrip cms = new ContextMenuStrip();
            this.InitializeImageList(cms);

            cms.Renderer = new RolloverItemRenderer();
            cms.AutoSize = true;
            cms.ShowCheckMargin = false;
            cms.ShowImageMargin = false;

            RolloverItem item = this.CreateRolloverItem(
                cms,
                "RolloverItem on ContextMenuStrip",
                f,
                handIconKey,
                TextImageRelation.ImageBeforeText,
                exclIconKey);

            cms.Items.Add(item);

            item = this.CreateRolloverItem(
                cms,
                "Another RolloverItem on ContextMenuStrip",
                f,
                questionIconKey,
                TextImageRelation.ImageBeforeText,
                exclIconKey);

            cms.Items.Add(item);

            item = this.CreateRolloverItem(
                cms,
                "And another RolloverItem on ContextMenuStrip",
                f,
                warningIconKey,
                TextImageRelation.ImageBeforeText,
                exclIconKey);

            cms.Items.Add(item);

            cms.Closing += new ToolStripDropDownClosingEventHandler(cms_Closing);

            this.button1.ContextMenuStrip = cms;
        }

        // This method handles the ContextMenuStrip 
        // control's Closing event. It prevents the 
        // RolloverItem from closing the drop-down  
        // when the item is clicked.
        void cms_Closing(object sender, ToolStripDropDownClosingEventArgs e)
        {
            if (e.CloseReason == ToolStripDropDownCloseReason.ItemClicked)
            {
                e.Cancel = true;
            }
        }

        // This method handles the Click event for the button.
        // it selects the first item in the ToolStrip control
        // by using the ToolStripITem.Select method.
        private void button1_Click(object sender, EventArgs e)
        {
            RolloverItem item = this.toolStrip1.Items[0] as RolloverItem;

            if (item != null)
            {
                item.Select();

                this.Invalidate();
            }
        }

        // This utility method creates a RolloverItem 
        // and adds it to a ToolStrip control.
        private RolloverItem CreateRolloverItem(
            ToolStrip owningToolStrip,
            string txt,
            Font f,
            string imgKey,
            TextImageRelation tir,
            string backImgKey)
        {
            RolloverItem item = new RolloverItem();

            item.Alignment = ToolStripItemAlignment.Left;
            item.AllowDrop = false;
            item.AutoSize = true;

            item.BackgroundImage = owningToolStrip.ImageList.Images[backImgKey];
            item.BackgroundImageLayout = ImageLayout.Center;
            item.DisplayStyle = ToolStripItemDisplayStyle.ImageAndText;
            item.DoubleClickEnabled = true;
            item.Enabled = true;
            item.Font = f;

            // These assignments are equivalent. Each assigns an
            // image from the owning toolstrip's image list.
            item.ImageKey = imgKey;
            //item.Image = owningToolStrip.ImageList.Images[infoIconKey];
            //item.ImageIndex = owningToolStrip.ImageList.Images.IndexOfKey(infoIconKey);
            item.ImageScaling = ToolStripItemImageScaling.None;

            item.Owner = owningToolStrip;
            item.Padding = new Padding(2);
            item.Text = txt;
            item.TextAlign = ContentAlignment.MiddleLeft;
            item.TextDirection = ToolStripTextDirection.Horizontal;
            item.TextImageRelation = tir;

            return item;
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        private void InitializeComponent()
        {
            this.toolStrip1 = new System.Windows.Forms.ToolStrip();
            this.button1 = new System.Windows.Forms.Button();
            this.SuspendLayout();
            // 
            // toolStrip1
            // 
            this.toolStrip1.AllowItemReorder = true;
            this.toolStrip1.Location = new System.Drawing.Point(0, 0);
            this.toolStrip1.Name = "toolStrip1";
            this.toolStrip1.Size = new System.Drawing.Size(845, 25);
            this.toolStrip1.TabIndex = 0;
            this.toolStrip1.Text = "toolStrip1";
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(12, 100);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(86, 23);
            this.button1.TabIndex = 1;
            this.button1.Text = "Click to select";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // RolloverItemTestForm
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 14F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.AutoSize = true;
            this.ClientSize = new System.Drawing.Size(845, 282);
            this.Controls.Add(this.button1);
            this.Controls.Add(this.toolStrip1);
            this.Font = new System.Drawing.Font("Arial", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.Name = "RolloverItemTestForm";
            this.Text = "Form1";
            this.ResumeLayout(false);
            this.PerformLayout();
        }

        #endregion
    }

    static class Program
    {   
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new RolloverItemTestForm());
        }
    }
}

Option Strict On
Option Explicit On

Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Drawing
Imports System.Drawing.Drawing2D
Imports System.Windows.Forms

' This class implements a ToolStripItem that highlights
' its border and text when the mouse enters its
' client rectangle. It has a clickable state which is
' exposed through the Clicked property and displayed
' by highlighting or graying out the item's image. 
Public Class RolloverItem
    Inherits ToolStripItem

   Private clickedValue As Boolean = False
   Private rolloverValue As Boolean = False
   
   Private imageRect As Rectangle
   Private textRect As Rectangle
   
   ' For brevity, this implementation limits the possible 
   ' TextDirection values to ToolStripTextDirection.Horizontal. 
   Public Overrides Property TextDirection() As ToolStripTextDirection
      Get
         Return MyBase.TextDirection
      End Get
      Set
         If value = ToolStripTextDirection.Horizontal Then
            MyBase.TextDirection = value
         Else
                Throw New ArgumentException( _
                "RolloverItem supports only horizontal text.")
         End If
      End Set
   End Property
   
   ' For brevity, this implementation limits the possible 
   ' TextImageRelation values to ImageBeforeText and TextBeforeImage. 
   Public Shadows Property TextImageRelation() As TextImageRelation
      Get
         Return MyBase.TextImageRelation
      End Get
      
      Set
            If Value = TextImageRelation.ImageBeforeText OrElse _
               Value = TextImageRelation.TextBeforeImage Then
                MyBase.TextImageRelation = Value
            Else
                Throw New ArgumentException("Unsupported TextImageRelation value.")
            End If
      End Set
   End Property
   
   ' This property returns true if the mouse is 
   ' inside the client rectangle.
   Public ReadOnly Property Rollover() As Boolean
      Get
         Return Me.rolloverValue
      End Get
    End Property

   ' This property returns true if the item 
   ' has been toggled into the clicked state.
   ' Clicking again toggles it to the 
   ' unclicked state.
   Public ReadOnly Property Clicked() As Boolean
      Get
         Return Me.clickedValue
      End Get
   End Property
   
   ' The method defines the behavior of the Click event.
   ' It simply toggles the state of the clickedValue field.
   Protected Overrides Sub OnClick(e As EventArgs)
      MyBase.OnClick(e)
      
        Me.clickedValue = Me.clickedValue Xor True
    End Sub

   ' The method defines the behavior of the DoubleClick 
   ' event. It shows a MessageBox with the item's text.
   Protected Overrides Sub OnDoubleClick(e As EventArgs)
      MyBase.OnDoubleClick(e)
      
      Dim msg As String = String.Format("Item: {0}", Me.Text)
      
      MessageBox.Show(msg)
    End Sub

   ' This method defines the behavior of the MouseEnter event.
   ' It sets the state of the rolloverValue field to true and
   ' tells the control to repaint.
   Protected Overrides Sub OnMouseEnter(e As EventArgs)
      MyBase.OnMouseEnter(e)
      
      Me.rolloverValue = True
      
      Me.Invalidate()
    End Sub
   
   ' This method defines the behavior of the MouseLeave event.
   ' It sets the state of the rolloverValue field to false and
   ' tells the control to repaint.
   Protected Overrides Sub OnMouseLeave(e As EventArgs)
      MyBase.OnMouseLeave(e)
      
      Me.rolloverValue = False
      
      Me.Invalidate()
    End Sub
   
   ' This method defines the painting behavior of the control.
   ' It performs the following operations:
   '
   ' Computes the layout of the item's image and text.
   ' Draws the item's background image.
   ' Draws the item's image.
   ' Draws the item's text.
   '
   ' Drawing operations are implemented in the 
   ' RolloverItemRenderer class.
   Protected Overrides Sub OnPaint(e As PaintEventArgs)
      MyBase.OnPaint(e)
      
      If (Me.Owner IsNot Nothing) Then
         ' Find the dimensions of the image and the text 
         ' areas of the item. 
         Me.ComputeImageAndTextLayout()
         
         ' Draw the background. This includes drawing a highlighted 
         ' border when the mouse is in the client area.
         Dim ea As New ToolStripItemRenderEventArgs(e.Graphics, Me)
         Me.Owner.Renderer.DrawItemBackground(ea)
         
         ' Draw the item's image. 
         Dim irea As New ToolStripItemImageRenderEventArgs(e.Graphics, Me, imageRect)
         Me.Owner.Renderer.DrawItemImage(irea)
         
         ' If the item is on a drop-down, give its
         ' text a different highlighted color.
            Dim highlightColor As Color = CType(IIf(Me.IsOnDropDown, Color.Salmon, SystemColors.ControlLightLight), Color)
         
         ' Draw the text, and highlight it if the 
         ' the rollover state is true.
            Dim rea As New ToolStripItemTextRenderEventArgs( _
               e.Graphics, _
               Me, _
               MyBase.Text, _
               textRect, _
               CType(IIf(Me.rolloverValue, highlightColor, MyBase.ForeColor), Color), _
               MyBase.Font, _
               MyBase.TextAlign)
         Me.Owner.Renderer.DrawItemText(rea)
      End If
    End Sub

   ' This utility method computes the layout of the 
   ' RolloverItem control's image area and the text area.
   ' For brevity, only the following settings are 
   ' supported:
   '
   ' ToolStripTextDirection.Horizontal
   ' TextImageRelation.ImageBeforeText 
   ' TextImageRelation.ImageBeforeText
   ' 
   ' It would not be difficult to support vertical text
   ' directions and other image/text relationships.
   Private Sub ComputeImageAndTextLayout()
      Dim cr As Rectangle = MyBase.ContentRectangle
      Dim img As Image = MyBase.Owner.ImageList.Images(MyBase.ImageKey)
      
      ' Compute the center of the item's ContentRectangle.
        Dim centerY As Integer = CInt((cr.Height - img.Height) / 2)
      
      ' Find the dimensions of the image and the text 
      ' areas of the item. The text occupies the space 
      ' not filled by the image. 
        If MyBase.TextImageRelation = _
        TextImageRelation.ImageBeforeText AndAlso _
        MyBase.TextDirection = ToolStripTextDirection.Horizontal Then

            imageRect = New Rectangle( _
            MyBase.ContentRectangle.Left, _
            centerY, _
            MyBase.Image.Width, _
            MyBase.Image.Height)

            textRect = New Rectangle( _
            imageRect.Width, _
            MyBase.ContentRectangle.Top, _
            MyBase.ContentRectangle.Width - imageRect.Width, _
            MyBase.ContentRectangle.Height)

        ElseIf MyBase.TextImageRelation = _
        TextImageRelation.TextBeforeImage AndAlso _
        MyBase.TextDirection = ToolStripTextDirection.Horizontal Then

            imageRect = New Rectangle( _
            MyBase.ContentRectangle.Right - MyBase.Image.Width, _
            centerY, _
            MyBase.Image.Width, _
            MyBase.Image.Height)

            textRect = New Rectangle( _
            MyBase.ContentRectangle.Left, _
            MyBase.ContentRectangle.Top, _
            imageRect.X, _
            MyBase.ContentRectangle.Bottom)

        End If
    End Sub
End Class

' This is the custom renderer for the RolloverItem control.
' It draws a border around the item when the mouse is
' in the item's client area. It also draws the item's image
' in an inactive state (grayed out) until the user clicks
' the item to toggle its "clicked" state.
Friend Class RolloverItemRenderer
    Inherits ToolStripSystemRenderer

    Protected Overrides Sub OnRenderItemImage(ByVal e As ToolStripItemImageRenderEventArgs)
        MyBase.OnRenderItemImage(e)

        Dim item As RolloverItem = CType(e.Item, RolloverItem)

        ' If the ToolSTripItem is of type RolloverItem, 
        ' perform custom rendering for the image.
        If (item IsNot Nothing) Then
            If item.Clicked Then
                ' The item is in the clicked state, so 
                ' draw the image as usual.
                e.Graphics.DrawImage(e.Image, e.ImageRectangle.X, e.ImageRectangle.Y)
            Else
                ' In the unclicked state, gray out the image.
                ControlPaint.DrawImageDisabled(e.Graphics, e.Image, e.ImageRectangle.X, e.ImageRectangle.Y, item.BackColor)
            End If
        End If
    End Sub

    ' This method defines the behavior for rendering the
    ' background of a ToolStripItem. If the item is a
    ' RolloverItem, it paints the item's BackgroundImage 
    ' centered in the client area. If the mouse is in the 
    ' item's client area, a border is drawn around it.
    ' If the item is on a drop-down or if it is on the
    ' overflow, a gradient is painted in the background.
    Protected Overrides Sub OnRenderItemBackground(ByVal e As ToolStripItemRenderEventArgs)
        MyBase.OnRenderItemBackground(e)

        Dim item As RolloverItem = CType(e.Item, RolloverItem)

        ' If the ToolSTripItem is of type RolloverItem, 
        ' perform custom rendering for the background.
        If (item IsNot Nothing) Then
            If item.Placement = ToolStripItemPlacement.Overflow OrElse item.IsOnDropDown Then
                Dim b As New LinearGradientBrush(item.ContentRectangle, Color.Salmon, Color.DarkRed, 0.0F, False)
                Try
                    e.Graphics.FillRectangle(b, item.ContentRectangle)
                Finally
                    b.Dispose()
                End Try
            End If

            ' The RolloverItem control only supports 
            ' the ImageLayout.Center setting for the
            ' BackgroundImage property.
            If item.BackgroundImageLayout = ImageLayout.Center Then
                ' Get references to the item's ContentRectangle
                ' and BackgroundImage, for convenience.
                Dim cr As Rectangle = item.ContentRectangle
                Dim bgi As Image = item.BackgroundImage

                ' Compute the center of the item's ContentRectangle.
                Dim centerX As Integer = CInt((cr.Width - bgi.Width) / 2)
                Dim centerY As Integer = CInt((cr.Height - bgi.Height) / 2)

                ' If the item is selected, draw the background
                ' image as usual. Otherwise, draw it as disabled.
                If item.Selected Then
                    e.Graphics.DrawImage(bgi, centerX, centerY)
                Else
                    ControlPaint.DrawImageDisabled(e.Graphics, bgi, centerX, centerY, item.BackColor)
                End If
            End If

            ' If the item is in the rollover state, 
            ' draw a border around it.
            If item.Rollover Then
                ControlPaint.DrawFocusRectangle(e.Graphics, item.ContentRectangle)
            End If
        End If
    End Sub

End Class

' This form tests various features of the RolloverItem
' control. RolloverItem conrols are created and added
' to the form's ToolStrip. They are also created and 
' added to a button's ContextMenuStrip. The behavior
' of the RolloverItem control differs depending on 
' the type of parent control.

Public Class RolloverItemTestForm
   Inherits Form
   Private toolStrip1 As System.Windows.Forms.ToolStrip
   Private WithEvents button1 As System.Windows.Forms.Button
   
   Private infoIconKey As String = "Information icon"
   Private handIconKey As String = "Hand icon"
   Private exclIconKey As String = "Exclamation icon"
   Private questionIconKey As String = "Question icon"
   Private warningIconKey As String = "Warning icon "
   
   Private components As System.ComponentModel.IContainer = Nothing
   
   
   Public Sub New()
      InitializeComponent()
      
      ' Set up the form's ToolStrip control.
      InitializeToolStrip()
      
      ' Set up the ContextMenuStrip for the button.
      InitializeContextMenu()
    End Sub
   
   
   ' This utility method initializes the ToolStrip control's 
   ' image list. For convenience, icons from the SystemIcons 
   ' class are used for this demonstration, but any images
   ' could be used.
   Private Sub InitializeImageList(ts As ToolStrip)
      If ts.ImageList Is Nothing Then
         ts.ImageList = New ImageList()
         ts.ImageList.ImageSize = SystemIcons.Exclamation.Size
         
         ts.ImageList.Images.Add(Me.infoIconKey, SystemIcons.Information)
         
         ts.ImageList.Images.Add(Me.handIconKey, SystemIcons.Hand)
         
         ts.ImageList.Images.Add(Me.exclIconKey, SystemIcons.Exclamation)
         
         ts.ImageList.Images.Add(Me.questionIconKey, SystemIcons.Question)
         
         ts.ImageList.Images.Add(Me.warningIconKey, SystemIcons.Warning)
      End If
    End Sub
   
   
   Private Sub InitializeToolStrip()
      Me.InitializeImageList(Me.toolStrip1)
      
      Me.toolStrip1.Renderer = New RolloverItemRenderer()
      
      Dim item As RolloverItem = Me.CreateRolloverItem(Me.toolStrip1, "RolloverItem on ToolStrip", Me.Font, infoIconKey, TextImageRelation.ImageBeforeText, exclIconKey)
      
      Me.toolStrip1.Items.Add(item)
      
      item = Me.CreateRolloverItem(Me.toolStrip1, "RolloverItem on ToolStrip", Me.Font, infoIconKey, TextImageRelation.ImageBeforeText, exclIconKey)
      
      Me.toolStrip1.Items.Add(item)
    End Sub
   
   
   Private Sub InitializeContextMenu()
        Dim f As New System.Drawing.Font("Arial", 18.0F, FontStyle.Bold)
      
      Dim cms As New ContextMenuStrip()
      Me.InitializeImageList(cms)
      
      cms.Renderer = New RolloverItemRenderer()
      cms.AutoSize = True
      cms.ShowCheckMargin = False
      cms.ShowImageMargin = False
      
        Dim item As RolloverItem = Me.CreateRolloverItem( _
        cms, _
        "RolloverItem on ContextMenuStrip", _
        f, _
        handIconKey, _
        TextImageRelation.ImageBeforeText, _
        exclIconKey)
      
      cms.Items.Add(item)
      
        item = Me.CreateRolloverItem( _
        cms, _
        "Another RolloverItem on ContextMenuStrip", _
        f, _
        questionIconKey, _
        TextImageRelation.ImageBeforeText, _
        exclIconKey)
      
      cms.Items.Add(item)
      
        item = Me.CreateRolloverItem( _
        cms, _
        "And another RolloverItem on ContextMenuStrip", _
        CType(f, Drawing.Font), _
        warningIconKey, _
        TextImageRelation.ImageBeforeText, _
        exclIconKey)
      
      cms.Items.Add(item)
      
      AddHandler cms.Closing, AddressOf cms_Closing
      
      Me.button1.ContextMenuStrip = cms
    End Sub
   
   
   ' This method handles the ContextMenuStrip 
   ' control's Closing event. It prevents the 
   ' RolloverItem from closing the drop-down  
   ' when the item is clicked.
   Private Sub cms_Closing(sender As Object, e As ToolStripDropDownClosingEventArgs)
      If e.CloseReason = ToolStripDropDownCloseReason.ItemClicked Then
         e.Cancel = True
      End If
    End Sub
   
   
   ' This method handles the Click event for the button.
   ' it selects the first item in the ToolStrip control
   ' by using the ToolStripITem.Select method.
   Private Sub button1_Click(sender As Object, e As EventArgs) Handles button1.Click
        Dim item As RolloverItem = CType(Me.toolStrip1.Items(0), RolloverItem)
      
      If (item IsNot Nothing) Then
         item.Select()
         
         Me.Invalidate()
      End If
    End Sub

   ' This utility method creates a RolloverItem 
   ' and adds it to a ToolStrip control.
    Private Function CreateRolloverItem( _
    ByVal owningToolStrip As ToolStrip, _
    ByVal txt As String, _
    ByVal f As Font, _
    ByVal imgKey As String, _
    ByVal tir As TextImageRelation, _
    ByVal backImgKey As String) As RolloverItem

        Dim item As New RolloverItem()

        item.Alignment = ToolStripItemAlignment.Left
        item.AllowDrop = False
        item.AutoSize = True

        item.BackgroundImage = owningToolStrip.ImageList.Images(backImgKey)
        item.BackgroundImageLayout = ImageLayout.Center
        item.DisplayStyle = ToolStripItemDisplayStyle.ImageAndText
        item.DoubleClickEnabled = True
        item.Enabled = True
        item.Font = f

        ' These assignments are equivalent. Each assigns an
        ' image from the owning toolstrip's image list.
        item.ImageKey = imgKey
        'item.Image = owningToolStrip.ImageList.Images[infoIconKey];
        'item.ImageIndex = owningToolStrip.ImageList.Images.IndexOfKey(infoIconKey);
        item.ImageScaling = ToolStripItemImageScaling.None

        item.Owner = owningToolStrip
        item.Padding = New Padding(2)
        item.Text = txt
        item.TextAlign = ContentAlignment.MiddleLeft
        item.TextDirection = ToolStripTextDirection.Horizontal
        item.TextImageRelation = tir

        Return item
    End Function

   Protected Overrides Sub Dispose(disposing As Boolean)
      If disposing AndAlso (components IsNot Nothing) Then
         components.Dispose()
      End If
      MyBase.Dispose(disposing)
    End Sub
   
   #Region "Windows Form Designer generated code"
   
   Private Sub InitializeComponent()
      Me.toolStrip1 = New System.Windows.Forms.ToolStrip()
      Me.button1 = New System.Windows.Forms.Button()
      Me.SuspendLayout()
      ' 
      ' toolStrip1
      ' 
      Me.toolStrip1.AllowItemReorder = True
      Me.toolStrip1.Location = New System.Drawing.Point(0, 0)
      Me.toolStrip1.Name = "toolStrip1"
      Me.toolStrip1.Size = New System.Drawing.Size(845, 25)
      Me.toolStrip1.TabIndex = 0
      Me.toolStrip1.Text = "toolStrip1"
      ' 
      ' button1
      ' 
      Me.button1.Location = New System.Drawing.Point(12, 100)
      Me.button1.Name = "button1"
      Me.button1.Size = New System.Drawing.Size(86, 23)
      Me.button1.TabIndex = 1
      Me.button1.Text = "Click to select"
      Me.button1.UseVisualStyleBackColor = True
      ' 
      ' RolloverItemTestForm
      ' 
      Me.AutoScaleDimensions = New System.Drawing.SizeF(6F, 14F)
      Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
      Me.AutoSize = True
      Me.ClientSize = New System.Drawing.Size(845, 282)
      Me.Controls.Add(button1)
      Me.Controls.Add(toolStrip1)
        Me.Font = New System.Drawing.Font("Arial", 8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, 0)
      Me.Name = "RolloverItemTestForm"
      Me.Text = "Form1"
      Me.ResumeLayout(False)
      Me.PerformLayout()
    End Sub
   
#End Region

End Class


Public Class Program

    <STAThread()> _
    Shared Sub Main()
        Application.EnableVisualStyles()
        Application.SetCompatibleTextRenderingDefault(False)
        Application.Run(New RolloverItemTestForm())
    End Sub
End Class

注解

是ToolStripItem按钮、组合框、文本框或标签等元素，可以包含在控件或ToolStripDropDown控件中ToolStrip，这类似于 Windows 快捷菜单。 类 ToolStrip 管理这些元素的绘图和键盘和鼠标输入（包括拖放输入），类 ToolStripItem 管理元素本身的事件和布局。

ToolStripItem 类直接从 ToolStripItem 继承，或是通过 ToolStripControlHost 或 ToolStripDropDownItem 间接从 ToolStripItem 继承。

ToolStripItem 控件必须包含在 ToolStrip、MenuStrip、StatusStrip 或 ContextMenuStrip 中，不能直接添加到窗体中。 各种容器类设计为包含 ToolStripItem 控件的适当子集。

注意 给定 ToolStripItem 的 不能有多个父 ToolStrip。 必须复制 并将其 ToolStripItem 添加到其他 ToolStrip 控件。

下表显示了派生自 类的元素，ToolStripItem因此这些元素可以托管在 或 ToolStripDropDown中ToolStrip。

构造函数

属性

方法

事件

显式接口实现

适用于

另请参阅

• ToolStrip
• ToolStripButton
• ToolStripLabel
• ToolStripSeparator
• ToolStripControlHost
• ToolStripComboBox
• ToolStripTextBox
• ToolStripDropDownItem
• ToolStripMenuItem
• ToolStripSplitButton
• ToolStripDropDownButton
• ToolStrip 控件（Windows 窗体）