This can be used to set some value which can be used programmatically. One other thing to be noted is, each control has one common property call “Tag”. If the control is valid, then it will remove the error message from the dictionary when there is any error. If the control is not valid, then it will add error message to the dictionary. Then, that control will be validated by the “ValidateSingleControl” method. ControlsValidating will get the control which raised the ‘Validating’ event, as a sender parameter. In my example, AttachHandlers method will attach event handler (Controls Validating) for both FirstName and LastName textboxes. So, whenever any control attached to that event lost focus, then the validation method will be called. i.e I have attached single validation method for multiple controls. So, I have used a single validation method to validate. But that is really going to be looking ugly when we have 15 or 20 textboxes or controls to be validated on a single form. You can have validating event for each text box. This event will be raised whenever the text box lost focus.

If we need to display error message whenever the textbox lost focus, then you may want to use “Validating” event that comes with the controls. This example will show error messages whenever the textboxes lost focus, or whenever the Submit button clicked.

txtFirstName, txtLastName, btnSubmit and CustomerDetailErrorProvider. CustomerDetailErrorProvider.SetError(txtFirstName, “First name is required”) įollowing example has two textboxes, button and an error provider control. Error provider will accept the field to which the error message should be displayed also, the error message which needs to be displayed. As you said Error providers can show error messages for the controls which are having seterror.

Vb.net remove errorprovider