Copying a Control between forms moves it instead

Question

I'm writing a Windows Forms application in VS 2015.

I have part of the form that I want to change, based on a radio selection. The part that I want to change I put in a Panel control.

My current plan was to create 4 control layouts on another form. I created Form2 and created 4 panels on it. I want to copy what's in those panels from Form2 to the Panel in Form1 when the radio button is clicked.

Currently, when I click each radio button, the controls in the Form2 Panel disappear! They are maybe getting moved, not copied. The first one I click does appear on Form 1, but the others do not after that first one. I don't want Form2 (RefPanels) to be changed at all. I just want to copy what's there to Form1. Here's the code I'm trying.

//RefPanels is my Form2 instance.
public Form2 RefPanels = new Form2();

//Each Radiobutton has something similar to this.
RadioBtn1_CheckChanged(...)
{
  Control[] cArray = new Control[20];
  RefPanels.Panel1.Controls.CopyTo(cArray, 0);

  foreach (Control c in cArray)
  {
    Form1_Destination_Panel.Controls.Add(c);
  }
}

I'm sure I'm going about this all wrong. Can you help?

Controls.CopyTo isn't doing a deep copy, only copying the references to the controls. That's why they are moving - when you add them to the destination panel you are adding the exiting control. — Kateract, Apr 11 '16 at 16:10

score 2 · Accepted Answer · edited May 23 '17 at 12:31

You are only copying the reference to your control. But a control can only be used in one form. So the control is dissapearing in the "old" form. You need real copies of your controls.

This Question describes a way to copy a control via reflection. Try it with a solution like this:

private void copyControl(Control sourceControl, Control targetControl)
{
    // make sure these are the same
    if (sourceControl.GetType() != targetControl.GetType())
    {
        throw new Exception("Incorrect control types");
    }

    foreach (PropertyInfo sourceProperty in sourceControl.GetType().GetProperties())
    {
        object newValue = sourceProperty.GetValue(sourceControl, null);

        MethodInfo mi = sourceProperty.GetSetMethod(true);
        if (mi != null)
        {
            sourceProperty.SetValue(targetControl, newValue, null);
        }
    }
}

Thanks! I had a feeling this was what was going on... But your linked answer helps clarify — Chris Vogel., Apr 12 '16 at 18:58

score 0 · Answer 2 · answered Apr 11 '16 at 16:25

0

I would accomplish this by creating a user control for each panel that contains the controls in your desired layout. Then, when you choose a different layout, you can create a new instance of the desired user control class and add that to the correct container. This will also allow you to keep the methods and such for the controls.

answered Apr 11 '16 at 16:25

Kateract

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15

Also add a copyData(myUCclass sourceUC) function to the UC so you can fill in the data from the source UC.. – TaW Apr 11 '16 at 17:20

Copying a Control between forms moves it instead

2 Answers2