Binding to ElementName in DataTemplate
I have one project where I need to validate a TextBox for a correct Text,Number or Date. I am using Validation rules in order to validate data. There is an other TextBlock where error message is shown. So I have a ContentControl which uses ContentTemplateSelector to select a DataTemplate based on data type (Text,Number or Date).
<DataTemplate x:Key="TextCriteria">
<TextBox DataContext="{Binding DataContext, RelativeSource={RelativeSource AncestorType=UserControl}}"
Text="{Binding Path=SelectedCriteria.DefaultValue, UpdateSourceTrigger=PropertyChanged}"
Name="TxtCriteriaValue">
</TextBox>
</DataTemplate>
<DataTemplate x:Key="NumberCriteria">
<Grid DataContext="{Binding DataContext, RelativeSource={RelativeSource AncestorType=UserControl}}">
<TextBox Name="TxtCriteriaValue">
<TextBox.Text>
<Binding Path="SelectedCriteria.DefaultValue" UpdateSourceTrigger="PropertyChanged" StringFormat="D" >
<Binding.ValidationRules>
<extra1:CriteriaNumberValueValidationRule ValidatesOnTargetUpdated="True"/>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>
</Grid>
</DataTemplate>
<DataTemplate x:Key="DateCriteria">
<Grid DataContext="{Binding DataContext, RelativeSource={RelativeSource AncestorType=UserControl}}">
<TextBox Name="TxtCriteriaValue">
<TextBox.Text>
<Binding Path="SelectedCriteria.DefaultValue" UpdateSourceTrigger="PropertyChanged" StringFormat="d">
<Binding.ValidationRules>
<extra1:CriteriaDateValueValidationRule ValidatesOnTargetUpdated="True"/>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>
</Grid>
</DataTemplate>
<extra1:CriteriaTypeTemplateSelector
x:Key="CriteriaTypeTemplateSelector"
TextDataTemplate="{StaticResource TextCriteria}"
NumberDataTemplate="{StaticResource NumberCriteria}"
DateDataTemplate="{StaticResource DateCriteria}" />
On the UserControl I have ContentControl with error TextBlock and a button for Accepting value:
<ContentControl Grid.Row="1"
Grid.Column="1"
x:Name="ContentControl"
ContentTemplateSelector="{StaticResource CriteriaTypeTemplateSelector}"
Content="{Binding SelectedCriteria.CriteriaValueType}"
IsTabStop="False"/>
<TextBlock Grid.Row="2" Grid.Column="1"
x:Name="ValidationErrorTextBlock"
Text="{Binding ElementName=TxtCriteriaValue, Path=(Validation.Errors)[0].ErrorContent,Converter={StaticResource DebugConverter}}">
<TextBlock.Style>
<Style TargetType="{x:Type TextBlock}">
<Setter Property="Visibility" Value="Collapsed"/>
<Style.Triggers>
<MultiDataTrigger>
<MultiDataTrigger.Conditions>
<Condition
Binding="{Binding (Validation.HasError), Converter={StaticResource ErrorCollectionToVisibility}, ElementName=TxtCriteriaValue}"
Value="True"/>
</MultiDataTrigger.Conditions>
<Setter Property="Visibility" Value="Visible"/>
</MultiDataTrigger>
</Style.Triggers>
</Style>
</TextBlock.Style>
</TextBlock>
<StackPanel Grid.Row="3" Grid.Column="1" HorizontalAlignment="Right" Orientation="Horizontal">
<Button Content="Accept"
IsDefault="True"
Name="AcceptButton"
Command="{Binding AcceptSingleValueCommand}">
<Button.Style>
<Style TargetType="{x:Type Button}" BasedOn="{StaticResource ToolTipBasicButton}">
<Setter Property="IsEnabled" Value="False"/>
<Style.Triggers>
<DataTrigger Binding="{Binding (Validation.HasError), ElementName=TxtCriteriaValue}" Value="False">
<Setter Property="IsEnabled" Value="True"/>
</DataTrigger>
</Style.Triggers>
</Style>
</Button.Style>
</Button>
</StackPanel>
Validations are working OK.
The problem is in Binding to TextBox in the DataTemplate. I am getting binding errors:
System.Windows.Data Error: 4 : Cannot find source for binding with reference 'ElementName=TxtCriteriaValue'. BindingExpression:Path=(0)[0].ErrorContent; DataItem=null; target element is 'TextBlock' (Name='ValidationErrorTextBlock'); target property is 'Text' (type 'String') System.Windows.Data Error: 4 : Cannot find source for binding with reference 'ElementName=TxtCriteriaValue'. BindingExpression:Path=(Validation.HasError); DataItem=null; target element is 'TextBlock' (Name='ValidationErrorTextBlock'); target property is 'NoTarget' (type 'Object') System.Windows.Data Error: 4 : Cannot find source for binding with reference 'ElementName=TxtCriteriaValue'. BindingExpression:Path=(Validation.HasError); DataItem=null; target element is 'Button' (Name='AcceptButton'); target property is 'NoTarget' (type 'Object')
How can I bind to control in the DataTemplate?
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