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VisualStyleRenderer.GetBackgroundRegion Method

.NET Framework 4

Other Versions

Returns the region for the background of the current visual style element.

Namespace: System.Windows.Forms.VisualStyles
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)

Syntax

C++

Copy

public Region GetBackgroundRegion(
	IDeviceContext dc,
	Rectangle bounds
)

Parameters

dc: Type: System.Drawing.IDeviceContext
The IDeviceContext this operation will use.

bounds: Type: System.Drawing.Rectangle
A Rectangle that contains the entire background area of the current visual style element.

Return Value

Type: System.Drawing.Region
The Region that contains the background of the current visual style element.

Exceptions

Exception	Condition
ArgumentNullException	dc is null.

Remarks

This method can be used to get the Region of a visual style element that has partially transparent or alpha-blended parts in its background.

Examples

The following code example demonstrates how to use the GetBackgroundRegion method in a custom control. This example uses GetBackgroundRegion to get the Region of the window title bar element returned by the VisualStyleElement.Window.Caption.Active property. This Region is used to set the Control.Region property of the control, so that the window title bar will appear with the rounded corners defined by the standard Windows XP visual style. This code example is part of a larger example provided for the VisualStyleRenderer class overview.

C++

Copy


// 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;
        }
    }
}

Version Information

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Reference

VisualStyleRenderer Class

System.Windows.Forms.VisualStyles Namespace

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