共用方式為


VisualStyleRenderer.GetBackgroundRegion(IDeviceContext, Rectangle) 方法

定義

傳回目前視覺化樣式項目的背景區域。

public:
 System::Drawing::Region ^ GetBackgroundRegion(System::Drawing::IDeviceContext ^ dc, System::Drawing::Rectangle bounds);
public System.Drawing.Region GetBackgroundRegion (System.Drawing.IDeviceContext dc, System.Drawing.Rectangle bounds);
public System.Drawing.Region? GetBackgroundRegion (System.Drawing.IDeviceContext dc, System.Drawing.Rectangle bounds);
member this.GetBackgroundRegion : System.Drawing.IDeviceContext * System.Drawing.Rectangle -> System.Drawing.Region
Public Function GetBackgroundRegion (dc As IDeviceContext, bounds As Rectangle) As Region

參數

dc
IDeviceContext

此作業將使用的 IDeviceContext

bounds
Rectangle

Rectangle,包含目前視覺化樣式項目的整個背景區域。

傳回

Region

Region,包含目前視覺化樣式項目的背景。

例外狀況

dcnull

範例

下列程式碼範例示範如何在自訂控制項中使用 GetBackgroundRegion 方法。 這個範例會使用 GetBackgroundRegion 取得 Region 屬性所 VisualStyleElement.Window.Caption.Active 傳回之視窗標題列專案的 。 這是 Region 用來設定 Control.Region 控制項的 屬性,讓視窗標題列會顯示為標準Windows XP 視覺化樣式所定義的圓角。 此程式碼範例是類別概觀所提供較大範例的 VisualStyleRenderer 一部分。

    // Calculate and set the clipping region for the control
    // so that the corners of the title bar are rounded.
private:
    void SetClipRegion()
    {
        if (!Application::RenderWithVisualStyles)
        {
            return;
        }

        Graphics^ g = this->CreateGraphics();
        // Get the current region for the window caption.
        if (SetRenderer(windowElements["windowCaption"]))
        {
            System::Drawing::Region^ clipRegion =
                renderer->GetBackgroundRegion(g,
                elementRectangles["windowCaption"]);

            // Get the client rectangle, but exclude the region
            // of the window caption.
            int height = (int)clipRegion->GetBounds(g).Height;
            System::Drawing::Rectangle nonCaptionRect = Rectangle(
                ClientRectangle.X, ClientRectangle.Y + height,
                ClientRectangle.Width, ClientRectangle.Height - height);

            // Add the rectangle to the caption region, and
            // make this region the form's clipping region.
            clipRegion->Union(nonCaptionRect);
            this->Region = clipRegion;
        }

    }
// Calculate and set the clipping region for the control  
// so that the corners of the title bar are rounded.
private void SetClipRegion()
{
    if (!Application.RenderWithVisualStyles)
    {
        return;
    }

    using (Graphics g = this.CreateGraphics())
    {
        // Get the current region for the window caption.
        if (SetRenderer(windowElements["windowCaption"]))
        {
            Region clipRegion = renderer.GetBackgroundRegion(
                g, elementRectangles["windowCaption"]);

            // Get the client rectangle, but exclude the region 
            // of the window caption.
            int height = (int)clipRegion.GetBounds(g).Height;
            Rectangle nonCaptionRect = new Rectangle(
                ClientRectangle.X,
                ClientRectangle.Y + height,
                ClientRectangle.Width,
                ClientRectangle.Height - height);

            // Add the rectangle to the caption region, and  
            // make this region the form's clipping region.
            clipRegion.Union(nonCaptionRect);
            this.Region = clipRegion;
        }
    }
}
' Calculate and set the clipping region for the control  
' so that the corners of the title bar are rounded.
Private Sub SetClipRegion()
    If Not Application.RenderWithVisualStyles Then
        Return
    End If

    Using g As Graphics = Me.CreateGraphics()
        ' Get the current region for the window caption.
        If SetRenderer(windowElements("windowCaption")) Then
            Dim clipRegion As Region = _
                renderer.GetBackgroundRegion(g, _
                elementRectangles("windowCaption"))

            ' Get the client rectangle, but exclude the   
            ' region of the window caption.
            Dim height As Integer = _
                CInt(clipRegion.GetBounds(g).Height)
            Dim nonCaptionRect As _
                New Rectangle(ClientRectangle.X, _
                ClientRectangle.Y + height, _
                ClientRectangle.Width, _
                ClientRectangle.Height - height)

            ' Add the rectangle to the caption region, and  
            ' make this region the form's clipping region.
            clipRegion.Union(nonCaptionRect)
            Me.Region = clipRegion
        End If
    End Using
End Sub

備註

這個方法可以用來取得 Region 在背景中具有部分透明或 Alpha 混合部分的視覺樣式專案。

適用於