Question

How do I implement a Copy menu item in a Windows application written in C#/.NET 2.0?

I want to let the user to mark some text in a control and then select the Copy menu item from an Edit menu in the menubar of the application and then do a Paste in for example Excel.

What makes my head spin is how to first determine which child form is active and then how to find the control that contains the marked text that should be copied to the clipboard.

Help, please.

Answer 1

With the aid of some heavy pair programming a colleague of mine and I came up with this, feel free to refactor.

The code is placed in the main form. The copyToolStripMenuItem_Click method handles the Click event on the Copy menu item in the Edit menu.

    /// <summary>     /// Recursively traverse a tree of controls to find the control that has focus, if any     /// </summary>     /// <param name='c'>The control to search, might be a control container</param>     /// <returns>The control that either has focus or contains the control that has focus</returns>     private Control FindFocus(Control c)      {         foreach (Control k in c.Controls)         {             if (k.Focused)             {                 return k;             }             else if (k.ContainsFocus)             {                 return FindFocus(k);             }         }          return null;     }      private void copyToolStripMenuItem_Click(object sender, EventArgs e)     {         Form f = this.ActiveMdiChild;          // Find the control that has focus         Control focusedControl = FindFocus(f.ActiveControl);          // See if focusedControl is of a type that can select text/data         if (focusedControl is TextBox)         {             TextBox tb = focusedControl as TextBox;             Clipboard.SetDataObject(tb.SelectedText);         }         else if (focusedControl is DataGridView)         {             DataGridView dgv = focusedControl  as DataGridView;             Clipboard.SetDataObject(dgv.GetClipboardContent());         }         else if (...more?...)         {         }     }