Child form opens on first screen when user has dragged the main form to the second screen

user_721660 0
Viewed 96

My Application's Main Form opens on the Laptop (main screen) when it starts. Then user drags it to the other screen (for big display), and opens a child form that is displayed on the Laptop screen rather than Application's Main Form (big display). I want the child form to open on the screen where Application's Main Form is open at the moment.

I tried following options, but they only worked in debug mode and did not work in production

ChildForm.ShowDialog((IWin32Window)this.MainForm);
ChildForm.ShowDialog(formMainInstance);
ChildForm.Show(formMainInstance);

I know about FormStartPosition.CenterParent, but it's not the right option for me. How can I do this?

winforms c#
2 Answers

As far as I know you have 3 options:

  1. Use FormStartPosition.CenterScreen;

         private void button2_Click(object sender, EventArgs e)
 {          
     Form2 child = new Form2();
     child.StartPosition = FormStartPosition.CenterScreen;
     child.ShowDialog(this);
 }

  2. Use FormStartPosition.CenterParent

    private void button2_Click(object sender, EventArgs e)
 {          
     Form2 child = new Form2();
     child.StartPosition = FormStartPosition.CenterParent;
     child.ShowDialog(this);
 }

    }

  3. Use FormStartPosition.Manual and pass a point

        private void button2_Click(object sender, EventArgs e)
 {          
     Form2 child = new Form2();
     child.StartPosition = FormStartPosition.Manual;
     child.Location = new System.Drawing.Point(0, 0);
     child.ShowDialog(this);
 }
user_42585070

The following code worked for me.

var screen = Screen.FromControl(childFormInstance);
var MainFormScreen = Screen.FromControl(_formMainInstance);
ChildForm.Left = MainFormScreen.WorkingArea.Left + 120;
ChildForm.Top = MainFormScreen.WorkingArea.Top + 120;
ChildForm.ShowDialog();
  1. First I query which screen the child form want to open
  2. Then I query which screen my Main form is currently open
  3. Then I overwrite the child form screen
user_7216600
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