C # winforms does not rule out exceptions in specific cases

Question

Trying to ask my question again - the last time it went bad.

This is my sample code:

• A small form containing only a button and combobox:

  public partial class question : Form
  {
  public question()
  {
      InitializeComponent();
  }
  
  private void button1_Click(object sender, EventArgs e)
  {
      comboBox1.DataSource = new List<string>() { "a", "b", "c" };
  }
  
  private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
  {
      MessageBox.Show("In comboBox1_SelectedIndexChanged");
      throw new Exception();
  }
  }
  

• Project Programclass that calls the form questionand handles exceptions:

   class Program
  {
  static void Main(string[] args)
  {
      try
      {
          Application.EnableVisualStyles();
          Application.SetCompatibleTextRenderingDefault(false);
  
          // Add the event handler for handling UI thread exceptions to the event.
          Application.ThreadException += new ThreadExceptionEventHandler(MyCommonExceptionHandlingMethod);
  
          // Set the unhandled exception mode to force all Windows Forms errors to go through
          // our handler.
          Application.SetUnhandledExceptionMode(UnhandledExceptionMode.CatchException);
  
          // Add the event handler for handling non-UI thread exceptions to the event. 
          AppDomain.CurrentDomain.UnhandledException +=
              new UnhandledExceptionEventHandler(CurrentDomain_UnhandledException);
  
          Application.Run(new question());
      }
      catch (Exception ex)
      {
          Console.WriteLine(ex.Message + "3");
      }
  }
  private static void MyCommonExceptionHandlingMethod(object sender, ThreadExceptionEventArgs t)
  {
      Console.WriteLine(t.Exception.Message + "1");
  }
  
  private static void CurrentDomain_UnhandledException(object sender, UnhandledExceptionEventArgs e)
  {
      Console.WriteLine(((Exception)e.ExceptionObject).Message + "2");
  }
  }
  

Now, with a single click on the button, the "SelectedIndexChanged" event is incremented (and a MessageBox appears) , but the exception is ignored. Only when the user manually selects another index in the combo box is an exception thrown.

The question is how to handle these exceptions too?

Answer 1

:

try
{
    comboBox1.DataSource = new List<string>() {"a", "b", "c"};
}
catch (Exception ex)
{
}

, ComboBox , DataSource:

ListControl.DataSource

try 
{
    SetDataConnection(value, displayMember, false);
} catch 
{
    DisplayMember = "";
}

ComboBox.DataSource ListControl