HiddenFieldDesigner 类

定义

public ref class HiddenFieldDesigner : System::Web::UI::Design::ControlDesigner

public class HiddenFieldDesigner : System.Web.UI.Design.ControlDesigner

type HiddenFieldDesigner = class
    inherit ControlDesigner

Public Class HiddenFieldDesigner
Inherits ControlDesigner

继承

Object

ComponentDesigner

HtmlControlDesigner

ControlDesigner

HiddenFieldDesigner

示例

下面的代码示例演示如何扩展 HiddenFieldDesigner 类，以在设计时更改派生自 控件的 HiddenField 控件的外观。

该示例从 HiddenField派生MyHiddenField控件。 MyHiddenField是 的副本HiddenField。 该示例还从 类派生MyHiddenFieldDesigner类，HiddenFieldDesigner并为 控件上的 MyHiddenField 应用 DesignerAttribute 属性MyHiddenFieldDesigner。

MyHiddenFieldDesigner重写 方法以GetDesignTimeHtml生成一个占位符，该占位符包含 Value 占位符中的 属性，以及控件类名称和 ID 属性。

using System;
using System.Web;
using System.Web.UI.WebControls;
using System.Web.UI.Design.WebControls;
using System.ComponentModel;
using System.Security.Permissions;

namespace Examples.CS.WebControls.Design
{
    // The MyHiddenField is a copy of the HiddenField.
    [AspNetHostingPermission(SecurityAction.Demand, 
        Level = AspNetHostingPermissionLevel.Minimal)]
    [AspNetHostingPermission(SecurityAction.InheritanceDemand, 
        Level = AspNetHostingPermissionLevel.Minimal)]
    [Designer(typeof(Examples.CS.WebControls.Design.MyHiddenFieldDesigner))]
    public class MyHiddenField : HiddenField
    {
    } // MyHiddenField

    // Derive a designer that inherits from the HiddenFieldDesigner.
    public class MyHiddenFieldDesigner : HiddenFieldDesigner
    {
        // Generate the design-time markup.
        public override string GetDesignTimeHtml()
        {
            // Get a reference to the control or a copy of the control.
            MyHiddenField myHF = (MyHiddenField)ViewControl;

            // Create a placeholder that displays the control value.
            string markup = CreatePlaceHolderDesignTimeHtml(
                 "Value: \"" + myHF.Value.ToString() + "\"" );

            return markup;
        } // GetDesignTimeHtml
    } // MyHiddenFieldDesigner
} // Examples.CS.WebControls.Design

Imports System.Web
Imports System.Web.UI.WebControls
Imports System.Web.UI.Design.WebControls
Imports System.ComponentModel
Imports System.Security.Permissions

Namespace Examples.VB.WebControls.Design

    ' The MyHiddenField is a copy of the HiddenField.
    <AspNetHostingPermission(SecurityAction.Demand, _
        Level:=AspNetHostingPermissionLevel.Minimal)> _
    <AspNetHostingPermission(SecurityAction.InheritanceDemand, _
        Level:=AspNetHostingPermissionLevel.Minimal)> _
    <Designer(GetType(Examples.VB.WebControls.Design.MyHiddenFieldDesigner))> _
    Public Class MyHiddenField
        Inherits HiddenField
    End Class

    ' Derive a designer that inherits from the HiddenFieldDesigner.
    Public Class MyHiddenFieldDesigner
        Inherits HiddenFieldDesigner

        ' Generate the design-time markup.
        Public Overrides Function GetDesignTimeHtml() As String

            ' Get a reference to the control or a copy of the control.
            Dim myHF As MyHiddenField = CType(ViewControl, MyHiddenField)

            Dim markup As String = _
                CreatePlaceHolderDesignTimeHtml( _
                    "Value: """ & myHF.Value.ToString() & """" )

            Return markup

        End Function ' GetDesignTimeHtml
    End Class
End Namespace ' Examples.VB.WebControls.Design

注解

在可视化设计器中，当用户从“源”视图切换到“设计”视图时，将分析描述 HiddenField 控件的标记源代码，并在设计图面上创建控件的设计时版本。 当用户切换回“源”视图时，设计时控件将保留到标记源代码中，并编辑到网页的标记中。 类 HiddenFieldDesigner 为 HiddenField 可视化设计器中的 提供设计时支持。

方法 GetDesignTimeHtml 返回用于在设计时呈现关联的 HiddenField 的标记。 方法 Initialize 使设计器准备好查看、编辑和设计关联的 HiddenField。

构造函数

属性

方法

显式接口实现

适用于

另请参阅

• HiddenField
• ControlDesigner
• HtmlControlDesigner
• ComponentDesigner
• ASP.NET 控件设计器简介
• 演练：为 Web 服务器控件创建基本控件设计器