Error Provider Control in Windows Forms

When using validation, programmer should have notify a message if there is a problem with the input entry. That notification can be shown using message box, status label control etc. The one more control to notify an error message to user is error provider control.

Error provider control can be used to display an error message, whenever the user positions the mouse pointer over the error icon. To add an error provider control, you can drag-n-drop it from the toolbox to the form. Some of the properties of this control are:

• BlinkStyle: whether the error icon blinks or not when an error is set.
• BlinkRate: rate at which the error icon blinks.
• ContainerControl: contains the controls on which this control can display icons.

Here are some methods which are mostly used with error provider:

• Clear(): clear all the errors associated with it.
• GetError(): returns current error string for the specified control.
• SetError(): set the error for specified control.

To set an error for a textbox when user left empty, drag-n-drop a textbox, button and an error provider control on a form. On the click event of button write following code in C# language:

if (textBox1.Text == string.Empty)
{
textBox1.Focus();
errorProvider1.SetError(textBox1, "This may not be Empty");
}

When we run the form and click on the button without writing anything in the textbox, then an error icon will blink just after the textbox with a message shown as a tool tip of the icon.

Here in the code a method SetError() have been used, it takes two parameters, one for the control (to which error will be associated) and the second for the message to be shown. A single error provider can easily be used with more than one control.

Status Strip Control