1. Message and Dialog Boxes .NET provides a set of classes and enumerations that make it easy to create a message or dialog window to interact with a user. The simplest approach is to use the MessageBox class and its versatile Show method. The other approach is to create a custom form and invoke it with the form's ShowDialog method. Both of these methods create modal forms.

2. MessageBox The MessageBox class uses its Show method to display a message box that may contain text, buttons, and even an icon. The Show method includes these overloads: Syntax : • static DialogResult Show( string msg) • static DialogResult Show( string msg, string caption ) • static DialogResult Show( string msg, string caption, MessageBoxButtons buttons ) • static DialogResult Show( string msg, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defBtn )

3. ShowDialog The ShowDialog method permits you to create a custom form that is displayed in modal mode. It is useful when you need a dialog form to display a few custom fields of information. Like the MessageBox , it uses buttons to communicate with the user. The form used as the dialog box is a standard form containing any controls you want to place on it. Although not required, the form's buttons are usually implemented to return a DialogResult enum value. The following code handles the Click event for the two buttons shown on the form in Figure. private void buttonOK_Click(object sender, System.EventArgs e) { this.DialogResult = DialogResult.OK; } private void buttonCancel_Click(object sender, System.EventArgs e) { this.DialogResult = DialogResult.Cancel; }