Maximize MDI child form

Question

I\'m working on a legacy WinForms MDI application and have some trouble making the child forms behave as I want. My objective is to have the child form always maxim

Answer 1

You can override the OnResize of each child form you want to make sure does not minimize. Or create a BaseForm and inherit all children forms from it.

protected override void OnResize(EventArgs e)
{
   this.WindowState = FormWindowState.Maximized;
}

Also, you can use X,y coordinates, but OnResize should be enough. Put this in the child form constructor:

   this.WindowState = FormWindowState.Maximized;

   Point NewLoc = Screen.FromControl(this).WorkingArea.Location;
   //Modifiy the location so any toolbars & taskbar can be easily accessed.
   NewLoc.X += 1;
   NewLoc.Y += 1;
   this.Location = NewLoc;

   Size NewSize = Screen.FromControl(this).WorkingArea.Size;
   //Modifiy the size so any toolbars & taskbar can be easily accessed.
   NewSize.Height -= 1;
   NewSize.Width -= 1;
   this.Size = NewSize;

   this.MinimumSize = this.Size;
   this.MaximumSize = this.MinimumSize;

I got the code for the X,Y from here: http://bytes.com/topic/c-sharp/answers/278649-how-do-i-prevent-form-resizing

Answer 2

This is how I overcame the same promblem, cannot remember where I found the code.

private const int WM_SYSCOMMAND = 0x112;
private const int SC_MINIMIZE = 0xF020;
private const int SC_MAXIMIZE = 0xF030;
private const int SC_CLOSE = 0xF060;
private const int SC_RESTORE = 0xF120;

protected override void WndProc(ref Message msg)
{
  if ((msg.Msg == WM_SYSCOMMAND) && 
    (((int)msg.WParam == SC_MINIMIZE) || ((int)msg.WParam == SC_MAXIMIZE) ||
    ((int)msg.WParam == SC_CLOSE)) || ((int)msg.WParam == SC_RESTORE))
    {
      //do nothing
    } // end if
    else
    {
      base.WndProc(ref msg);
     } // end else
}

Answer 3

In my app I found if I put just these two lines in the form loaded event it worked. Thanks sarvjeet for the basic idea. +1 for you

this.WindowState = FormWindowState.Minimized;
this.WindowState = FormWindowState.Maximized;

Answer 4

The problem wasn't easy to solve, but I accidentally found the answer and it's quite simple; set the windowstate of the child form to Normal by default. Then make sure that you reset the windowstate of the child window AFTER you call the Show() method.

Example:

private void ShowNewForm(object sender, EventArgs e)
{
  Form childForm = new Form();
  childForm.MdiParent = this;
  childForm.Text = "Window " + childFormNumber++;
  childForm.Show();
  childForm.WindowState = FormWindowState.Maximized;
}

Answer 5

form1 obj = new form1 ();
obj.MdiParent = MDIGracular.ActiveForm;
obj.StartPosition = FormStartPosition.CenterParent;
obj.WindowState = FormWindowState.Minimized;
obj.Dock = DockStyle.Fill;
obj.Show();
obj.WindowState = FormWindowState.Maximized;