Custom validation of textbox in WPF - wpf

Question

So I'm trying to do something along this example: http://www.codeproject.com/KB/WPF/wpfvalidation.aspx
My Textbox currently looks like this:
<TextBox Height="23" HorizontalAlignment="Left" Margin="118,60,0,0" Name="CreateUserCPRTextbox" VerticalAlignment="Top" Width="120" >
<TextBox.Text>
<Binding Path="Name" UpdateSourceTrigger="LostFocus">
<Binding.ValidationRules>
<validators:TextRangeValidator
MinimumLength="10"
MaximumLength="10"
ErrorMessage="ID has to be 10 letters" />
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>
I've directly copied my TextRangeValidator from the example on that website. Nothing happens when I lose focus on the textbox. No matter what I type in it. Any Ideas? :)

Answer 1

Have you set the Validation.ErrorTemplate? It is defined as below in the Application.Resources in the example.You may have missed that
<Application.Resources>
<Style TargetType="{x:Type TextBox}">
<Setter Property="Validation.ErrorTemplate">
<Setter.Value>
<ControlTemplate>
<DockPanel LastChildFill="True">
<TextBlock DockPanel.Dock="Right"
Foreground="Orange"
Margin="5"
FontSize="12pt"
Text="{Binding ElementName=MyAdorner,
Path=AdornedElement.(Validation.Errors)[0].ErrorContent}">
</TextBlock>
<Border BorderBrush="Green" BorderThickness="3">
<AdornedElementPlaceholder Name="MyAdorner" />
</Border>
</DockPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="Validation.HasError" Value="true">
<Setter Property="ToolTip"
Value="{Binding RelativeSource={RelativeSource Self},
Path=(Validation.Errors)[0].ErrorContent}"/>
</Trigger>
</Style.Triggers>
</Style>
</Application.Resources>
EDIT
Your default value is not triggering the validation routine.To force it to validate for default value you have to set
<validators:TextRangeValidator ValidatesOnTargetUpdated="True"
MinimumLength="10"
MaximumLength="10"
ErrorMessage="ID has to be 10 letters" />

Answer 2

I think you need to set ValidatesOnDataErrors=True in binding for Text to make it work

Answer 3

WPF TextBox Validation
<Style x:Key="TextBoxInError" TargetType="TextBox">
<Setter Property="Validation.ErrorTemplate">
<Setter.Value>
<ControlTemplate>
<DockPanel>
<Grid>
<Polygon Points="20,10,20,0 0,0"
Stroke="Black"
StrokeThickness="1"
Fill="Red"
HorizontalAlignment="Right"
VerticalAlignment="Top"
ToolTip="{Binding ElementName=adorner,
Path=AdornedElement.(Validation.Errors)[0].ErrorContent}"/>
<AdornedElementPlaceholder x:Name="adorner"/>
<AdornedElementPlaceholder Name="customAdorner" VerticalAlignment="Center" >
<Border BorderBrush="red" BorderThickness="1" />
</AdornedElementPlaceholder>
</Grid>
<Border Background="Red" DockPanel.Dock="right" Margin="5,0,0,0"
Width="150" Height="20" CornerRadius="5"
ToolTip="{Binding ElementName=customAdorner,
Path=AdornedElement.(Validation.Errors)[0].ErrorContent}">
<TextBlock Text= "{Binding ElementName=customAdorner,
Path=AdornedElement.(Validation.Errors)[0].ErrorContent}" VerticalAlignment="center" HorizontalAlignment="Left"
FontWeight="Bold" Foreground="white" Width="250" />
</Border>
</DockPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
<Style.Triggers>
<Trigger Property="Validation.HasError" Value="True">
<Setter Property="ToolTip"
Value="{Binding RelativeSource={x:Static RelativeSource.Self},
Path=(Validation.Errors)[0].ErrorContent}" />
</Trigger>
</Style.Triggers>
</Style>