How to create a WPF validation rule to ensure two text fields have the same value?

.net, c#, validation, wpf, xaml

Solution

Looks like implementing the `System.ComponentModel.IDataErrorInfo` interface and adding `ValidatesOnDataErrors` did the trick.

<TextBox Name="Value2TextBox">    
    <TextBox.Text>        
        <BindingPath Path="Value2" UpdateSourceTrigger="PropertyChanged" ValidatesOnDataErrors="True" />
    </TextBox.Text>
</TextBox>

Problem

How would I create a validation rule to ensure Value2 has the same value as Value1? If a validation rule is not the best method then what would be better? I could have the TextChanged event handle this, but I'm wondering if there is something more elegant. ``` <TextBox Name="Value1TextBox"> <TextBox.Text> <BindingPath Path="Value1" UpdateSourceTrigger="PropertyChanged" /> </TextBox.Text> </TextBox> <TextBox Name="Value2TextBox"> <TextBox.Text> <BindingPath Path="Value2" UpdateSourceTrigger="PropertyChanged" /> </TextBox.Text> </TextBox> ```

Original source