private void listTasks_DoubleClick(object sender, EventArgs e) { // Check for item click. if (listTasks.SelectedItems[0] != null) { // Check item is completed. if (listTasks.SelectedItems[0].Tag != null) { AsyncTestResult result = new AsyncTestResult(); result.ShowList((string)listTasks.SelectedItems[0].Tag); result.ShowDialog(); result.Dispose(); } } }