Question: I want to create the rounded corner container in winform .net. My aim is to create a container such that if I dropped any other control within it, that control will also become round shape.

Is this possible?

Answer: 
You're looking for the [**`Control.Region`** property](http://msdn.microsoft.com/en-us/library/system.windows.forms.control.region.aspx), which allows you to set the window region associated with a particular control. The operating system will not draw or display any portion of a window that lies outside of a window region.

The documentation gives a sample of how to use the `Region` property to create a round button:

```
// This method will change the square button to a circular button by 
// creating a new circle-shaped GraphicsPath object and setting it 
// to the RoundButton objects region.
private void roundButton_Paint(object sender, PaintEventArgs e)
{
    System.Drawing.Drawing2D.GraphicsPath buttonPath = 
                            new System.Drawing.Drawing2D.GraphicsPath();

    // Set a new rectangle to the same size as the button's 
    // ClientRectangle property.
    System.Drawing.Rectangle newRectangle = roundButton.ClientRectangle;

    // Decrease the size of the rectangle.
    newRectangle.Inflate(-10, -10);

    // Draw the button's border.
    e.Graphics.DrawEllipse(System.Drawing.Pens.Black, newRectangle);

    // Increase the size of the rectangle to include the border.
    newRectangle.Inflate( 1,  1);

    // Create a circle within the new rectangle.
    buttonPath.AddEllipse(newRectangle);

    // Set the button's Region property to the newly created 
    // circle region.
    roundButton.Region = new System.Drawing.Region(buttonPath);
}

```
[Control.ControlAdded Event](http://msdn.microsoft.com/en-us/library/system.windows.forms.control.controladded.aspx)

[Control.Region](http://msdn.microsoft.com/en-us/library/system.windows.forms.control.region.aspx)

[Control.DesignMode](http://msdn.microsoft.com/en-us/library/system.web.ui.control.designmode.aspx)

You can alter the Region of child controls when they are added to the parent control.