.NET Windows Forms in a Nutshell

Name

ErrorProvider

Synopsis

This component allows you to display a small Icon next to a Control to indicate that there is something wrong with the user input. When the user hovers the mouse over the icon, a ToolTip appears containing some text descriptive of the error.

First, you must set the ContainerControl property to the container for the controls that need validation. This happens automatically if the ErrorProvider is dropped onto a designer surface. You can also set a specific Icon if the default red circle with a white exclamation is not to your taste or culture. The position at which an icon should appear is set using the Get/SetIconAlignment() and Get/SetIconPadding() methods. The icon can also be made to blink using the BlinkRate and BlinkStyle properties. (See ErrorBlinkStyle for more information about this).

There are two principle modes of operation. The simplest is to set the DataSource property to refer to a System.Data.DataSet, and you will automatically get errors displayed for any rows that have a column error (either set by the framework, or with the System.Data.DataRow.SetColumnError() method).

The alternative is to use the SetError() method, which allows you to set specific error text for any control. To clear the error condition, call SetError() for the control with an empty string (“”).

public class ErrorProvider : System.ComponentModel.Component : System.ComponentModel.IExtenderProvider {

// Public Constructors

   public ErrorProvider();

   public ErrorProvider(ContainerControl ...