Data validation using IDataErrorInfo

As per a previous post, how do you do data validation in WPF using IDataErrorInfo?

Well what does IDataErrorInfo give you? It defines two properties:

public string Error
{
get;
}

public string this[string columnName]
{
get;
}

When you implement these, you provide error validation for your WPF application.

How does that happen?
Well, it doesn’t automatically of course [no surprises there].

When you specify your binding in xaml, you need to specify either the ValidationRules element or the ValidatesOnDataErrors parameter:

<Binding Source=”{StaticResource tradeList}” Path=”Instrument” UpdateSourceTrigger=”PropertyChanged”>

<Binding.ValidationRules>

<DataErrorValidationRule>

</Binding.ValidationRules>

</Binding>

or

<Binding Source=”{StaticResource tradeList}” Path=”Instrument” ValidatesOnDataErrors=”true” />