Private Sub CheckBox1_CheckedChanged(ByVal sender As System.Object, _
   ByVal e As System.EventArgs) Handles CheckBox1.CheckedChanged
   ' Determine the CheckState of the check box.
   If CheckBox1.CheckState = CheckState.Checked Then
      ' If checked, do not allow items to be dragged onto the form.
      Me.AllowDrop = False
   End If
End Sub

private void checkBox1_CheckedChanged(object sender, System.EventArgs e)
{
   // Determine the CheckState of the check box.
   if (checkBox1.CheckState == CheckState.Checked) 
   {
      // If checked, do not allow items to be dragged onto the form.
      this.AllowDrop = false;
   }
}

private void checkBox1_CheckedChanged(System.Object sender, System.EventArgs e) 
{
   // Determine the CheckState of the check box. 
   if ( checkBox1.get_CheckState() == CheckState.Checked  ) 
   {
      // If checked, do not allow items to be dragged onto the form. 
      this.set_AllowDrop(false);
   }
}

private:
   void checkBox1_CheckedChanged(System::Object ^ sender,
      System::EventArgs ^ e)
   {
      // Determine the CheckState of the check box.
      if (checkBox1->CheckState == CheckState::Checked) 
      {
         // If checked, do not allow items to be dragged onto the form.
         this->AllowDrop = false;
      }
   }