Textarea not validating
Once you have created a converter class you will typically add it as a resource in XAML with a unique x: Key attribute and then reference it from the binding as a Static Resource: (string) to a dependency property of type string you don’t necessarily need to use a converter as the default conversion will automatically apply the To String() method on the value of the source property.
This means that you don’t have to use a converter to display a If a user enters an invalid value that cannot be converted to an int and be set as the value for the Age property in the view model in the above example, a validation error will occur and a visual feedback will be provided to the user to indicate this.
Please help me with the required code This is Xaml code: , you can do the validation in that instead of the setter of a particular property, then whenever there is a error, return an error message so that the text box which has the error gets a red box around it, indicating an error.
To get it done only with XAML you need to add Validation Rules for individual properties.
Error Template attached property of the control: Note that the Validation.
Error Template will be displayed on the adorner layer.
Note that the Text Block will appear on top of any elements that are located right below the Text Box as adorners are always visually on top.By default you will see a red border around the UI element when this happens, e.g.if you are typing a letter into a Text Box bound to a source property of type int: The actual message that is describing the error is stored in the Error Content property of a objects in it, another attached property named Validation. To be able to see the error messages in the view you can replace the default control template that draws the red border around the element with your own custom template by setting the Validation.WPF ships with two built-in concrete implementations of the object to the Validation.Errors collection when an exception is thrown in the setter of the source property.
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If you don’t specify a source explicitly by setting the Source property of the binding, it will inherit the Data Context from its parent element to use as its source.