Question

I have a windows form which I am using as a desktop application.
Now I want that the form should not go outside desktop borders when I drag it.
I know that the whole window doesnt disappear but I want to display all four corners.
I have set the “border style = Fixed Tool window”,and coded to move form programmatically.

So instead of this:

----------------------
!                    !
!          ---------------
!          !             !
!          !             !
!          ---------------
!                    !
----------------------

I want this:

------------------------
!                      !
!         -------------!
!         !           !!
!         !           !!
!         -------------!
!                      !
------------------------

Answer 1

You can use the LocationChanged event and compare it to Screen.AllScreens[0].Bounds this is the primary monitor, if you have multiple monitors you could change then index to select which screen you limit your form to.

private void Form1_LocationChanged(object sender, EventArgs e)
{
    if ((this.Left + this.Width) > Screen.AllScreens[0].Bounds.Width)
        this.Left = Screen.AllScreens[0].Bounds.Width - this.Width;

    if (this.Left  < Screen.AllScreens[0].Bounds.Left)
        this.Left = Screen.AllScreens[0].Bounds.Left;

    if ((this.Top + this.Height) > Screen.AllScreens[0].Bounds.Height)
        this.Top = Screen.AllScreens[0].Bounds.Height - this.Height;

    if (this.Top < Screen.AllScreens[0].Bounds.Top)
        this.Top = Screen.AllScreens[0].Bounds.Top;
}