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Validating event visual basic

validating event visual basic-63

But the key components, which the end-users interact with, are those which reside in the presentation layer.Therefore, this is the first place where the validation should be done.

validating event visual basic-54validating event visual basic-71

And finally, Inherit value means that the control's behavior is determined by the Auto Validate setting of his parent.The Validating event is intended to fire immediately after input has been completed but not accepted as valid.The Validated event is fired when the input is accepted as valid.The example is based on a Windows Forms control developed by me which is based on the Text Box control and handles validation in a standardized way in order to detect input errors and display them to users.Validation in Windows Forms Validations concerns about checking data entry and making sure it is valid based on the criteria of the application requirements.If you set an error message for a control, then an error icon is shown next to the control and will also display a tooltip when you hover the mouse over the error icon.

You set the error message for a control by calling the Set Error method on the error provider instance.

As well as the Error Provider component notifies the user of any validation problems.

In complex controls like Data Grid View control, we have built-in support for displaying validation errors as well.

A problem with this approach is that if the users enter an invalid value and tries to close the application, by default, they won't be able to do it. NET 2.0, we have the Auto Validate property on the Form class that lets you specify exactly what the behavior should be when the validation error occurs at the control level.

The Auto Validate property may have four values: Disable, Enable Prevent Focus Change, Enable Allow Focus Change, Inherit. If you set Enable Prevent Focus Change value and Cancel is set to true, focus will remain on the control that failed the validation.

You can validate down in the Control hierarchy by using the Validate and Validate Children method on container controls such as Forms.