how to set dialogresult yes in c# custom dialog box

public void CreateMyForm()
 {
    // Create a new instance of the form.
    Form form1 = new Form();
    // Create two buttons to use as the accept and cancel buttons.
    Button button1 = new Button ();
    Button button2 = new Button ();
   
    // Set the text of button1 to "OK".
    button1.Text = "OK";
    // Set the position of the button on the form.
    button1.Location = new Point (10, 10);
    // Set the text of button2 to "Cancel".
    button2.Text = "Cancel";
    // Set the position of the button based on the location of button1.
    button2.Location 
       = new Point (button1.Left, button1.Height + button1.Top + 10);
    // Make button1's dialog result OK.
    button1.DialogResult = DialogResult.OK;
    // Make button2's dialog result Cancel.
    button2.DialogResult = DialogResult.Cancel;
    // Set the caption bar text of the form.   
    form1.Text = "My Dialog Box";
 
    // Define the border style of the form to a dialog box.
    form1.FormBorderStyle = FormBorderStyle.FixedDialog;
    // Set the accept button of the form to button1.
    form1.AcceptButton = button1;
    // Set the cancel button of the form to button2.
    form1.CancelButton = button2;
    // Set the start position of the form to the center of the screen.
    form1.StartPosition = FormStartPosition.CenterScreen;
    
    // Add button1 to the form.
    form1.Controls.Add(button1);
    // Add button2 to the form.
    form1.Controls.Add(button2);
    
    // Display the form as a modal dialog box.
    form1.ShowDialog();
 
    // Determine if the OK button was clicked on the dialog box.
    if (form1.DialogResult == DialogResult.OK)
    {
       // Display a message box indicating that the OK button was clicked.
       MessageBox.Show("The OK button on the form was clicked.");
       // Optional: Call the Dispose method when you are finished with the dialog box.
       form1.Dispose();
    }
    else
    {
       // Display a message box indicating that the Cancel button was clicked.
       MessageBox.Show("The Cancel button on the form was clicked.");
       // Optional: Call the Dispose method when you are finished with the dialog box.
       form1.Dispose();
    }
 }