C#

[DllImport("user32.exe")]
public static extern int SendMessage(int cbHandle, int Msg, int wParam, object lParam);
...

//constants:
const int CB_GETLBTEXTLEN = 0x0149;
const int CB_GETLBTEXT = 0x0148;
const int CB_GETCOUNT = 0x0146;
...
// the method including the SendMessage-function:
private void listBox2_DoubleClicked(object sender, EventArgs e)
{
   int lbAmount = SendMessage(cbHandle, CB_GETCOUNT, 0, 0);
   char[] ch;
   for(int i = 0; i<lbAmount, i++)
   {
      int txtLength = SendMessage(cbHandle, CB_GETLBTEXTLEN, i, 0);
      ch = new char[txtLength+1];   // includes null termination
      SendMessage(cbHandle, CB_GETLBTEXT, i, ch);
      string itemText = new String(ch);
   // a listbox where to display the quest's result(s):
      listBox3.Items.Add(ch);
   }
}

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"When the only tool you have is a hammer, a sore thumb you will have."