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ValidationRule for WPF Text Box

I am new to WPF. In my UserControl, I have 8 labels and corresponding 8 text fields as follows:

1.Label : abc   2.Label : def
  TextBox1 :        TextBox2 :

3.Label :xyz    4. Label : ghi
  Textbox3 :        TextBox4 :

Each of these text properties textbox should contain text, ending with an appropriate name for the label TextBox1.textshould be xxxx.abc, TextBox2.textmust be xxxx.def and so on. If the text box should not have a red border.

Hope I understood the details. So what do I need to write different ValidationRulefor each text field?

Any data you enter

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1 answer

Why not create one implementation ValidationRule, with an expression of what should end with a field, for example:

public class EndsWithValidationRule : ValidationRule
{
    public string MustEndWith { get; set; }

    public override ValidationResult Validate(object value, CultureInfo cultureInfo)
    {
        var str = value as string;
        if(str == null)
        {
            return new ValidationResult(false, "Please enter some text");
        }
        if(!str.EndsWith(MustEndWith))
        {
            return new ValidationResult(false, String.Format("Text must end with '{0}'", MustEndWith));
        }
        return new ValidationResult(true, null);

    }
}

Then you can use it like this:

<TextBox x:Name="TextBox1">
    <TextBox.Text>
        <Binding Path="BoundProperty1" UpdateSourceTrigger="PropertyChanged">
            <Binding.ValidationRules>
                <local:EndsWithValidationRule MustEndWith=".def" />
            </Binding.ValidationRules>
        </Binding>
    </TextBox.Text>
</TextBox>

<TextBox x:Name="TextBox2">
    <TextBox.Text>
        <Binding Path="BoundProperty2" UpdateSourceTrigger="PropertyChanged">
            <Binding.ValidationRules>
                <local:EndsWithValidationRule MustEndWith=".abc" />
            </Binding.ValidationRules>
        </Binding>
    </TextBox.Text>
</TextBox>
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