Change Control Size Automatically with Form Size Change

Here is how you can change a form control size automatically when the form size is changed by user.
Declare a class variable that will hold the value of the current form size, and set its value in the contructor.

Size curSize;

public Form1()

{

InitializeComponent();

curSize = this.Size;

}

To capture form size change, use the ClientSizeChanged event handler with the following code:

private void Form1_ClientSizeChanged(object sender, EventArgs e)

{

    int heightDif = Size.Height - curSize.Height;

    int widthDif = Size.Width - curSize.Width;

    yourControlName.Height += heightDif;

    yourControlName.Width += widthDif;

    //store the current size until the next time this event is raised

    curSize = this.Size;

}