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 1

You’re looking for the Control.Region property, 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);
}