ScrollBar.Value 属性
定义
重要
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获取或设置表示滚动框在滚动条控件中的当前位置的数值。
public:
property int Value { int get(); void set(int value); };[System.ComponentModel.Bindable(true)]
public int Value { get; set; }[<System.ComponentModel.Bindable(true)>]
member this.Value : int with get, setPublic Property Value As Integer属性值
处于 Minimum 和 Maximum 范围内的数值。 默认值为 0。
- 属性
例外
示例
以下示例滚动图片框中的图像。 每当用户滚动时，它都使用 Value 滚动条的 来重绘图像的新部分。 此代码示例是为类概述提供的更大示例的 ScrollBar 一部分。
注意
有关如何在 Visual Studio 中运行此示例的说明，请参阅如何：使用 Visual Studio 编译和运行完整的Windows 窗体代码示例。
private void HandleScroll(Object sender, ScrollEventArgs e)
{
//Create a graphics object and draw a portion of the image in the PictureBox.
Graphics g = pictureBox1.CreateGraphics();
int xWidth = pictureBox1.Width;
int yHeight = pictureBox1.Height;
int x;
int y;
if (e.ScrollOrientation == ScrollOrientation.HorizontalScroll)
{
x = e.NewValue;
y = vScrollBar1.Value;
}
else //e.ScrollOrientation == ScrollOrientation.VerticalScroll
{
y = e.NewValue;
x = hScrollBar1.Value;
}
g.DrawImage(pictureBox1.Image,
new Rectangle(0, 0, xWidth, yHeight), //where to draw the image
new Rectangle(x, y, xWidth, yHeight), //the portion of the image to draw
GraphicsUnit.Pixel);
pictureBox1.Update();
}
Private Sub HandleScroll(ByVal sender As [Object], ByVal e As ScrollEventArgs) _
Handles vScrollBar1.Scroll, hScrollBar1.Scroll
'Create a graphics object and draw a portion of the image in the PictureBox.
Dim g As Graphics = pictureBox1.CreateGraphics()
Dim xWidth As Integer = pictureBox1.Width
Dim yHeight As Integer = pictureBox1.Height
Dim x As Integer
Dim y As Integer
If (e.ScrollOrientation = ScrollOrientation.HorizontalScroll) Then
x = e.NewValue
y = vScrollBar1.Value
Else 'e.ScrollOrientation == ScrollOrientation.VerticalScroll
y = e.NewValue
x = hScrollBar1.Value
End If
'First Rectangle: Where to draw the image.
'Second Rectangle: The portion of the image to draw.
g.DrawImage(pictureBox1.Image, _
New Rectangle(0, 0, xWidth, yHeight), _
New Rectangle(x, y, xWidth, yHeight), _
GraphicsUnit.Pixel)
pictureBox1.Update()
End Sub
