Question

I have read about Control.PointToClient or Control.PointToScreen on MSDN.

But how to show another form as same location as TextBoxwhen Button clicked, if I have this control hierarchy ?

+- Form
+--- Panel
+---- Panel
+------ TextBox
+------ Button

Answer 1

Use PointToScreen with an empty point (0, 0) to get the location of the control relative to the screen, then just show the form there (make sure StartPosition is Manual):

Point controlPosition = myTextBox.PointToScreen(Point.Empty);
MyForm newForm = new MyForm();
newForm.Location = controlPosition;
newForm.Show(this);