Specify Validation Rules for a Binding
<Window
x:Class="WpfApplication1.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:WpfApplication1="clr-namespace:WpfApplication1"
Title="WPF" Height="100" Width="280">
<Window.Resources>
<Style
x:Key="textBoxInErrorStyle"
TargetType="{x:Type TextBox}" >
<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>
<Setter Property="Validation.ErrorTemplate">
<Setter.Value>
<ControlTemplate>
<DockPanel DockPanel.Dock="Right">
<AdornedElementPlaceholder/>
<Image Source="Error.png" Width="16" Height="16"
ToolTip="{Binding Path=AdornedElement.ToolTip, RelativeSource={RelativeSource
Mode=FindAncestor,
AncestorType={x:Type Adorner}}}"/>
</DockPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</Window.Resources>
<StackPanel>
<Slider Name="slider" Margin="4" Interval="1" TickFrequency="1" IsSnapToTickEnabled="True" Minimum="0" Maximum="100"/>
<StackPanel Orientation="Horizontal" >
<TextBox Style="{StaticResource textBoxInErrorStyle}" HorizontalAlignment="Center" >
<TextBox.Text>
<Binding ElementName="slider" Path="Value" Mode="TwoWay"
UpdateSourceTrigger="PropertyChanged" >
<Binding.ValidationRules>
<WpfApplication1:PercentageRule/>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>
</StackPanel>
</StackPanel>
</Window>
//File:Window.xaml.vb
Imports System.Globalization
Imports System.Windows.Controls
Namespace WpfApplication1
Public Class PercentageRule
Inherits ValidationRule
Public Overrides Function Validate(value As Object, cultureInfo As CultureInfo) As ValidationResult
Dim stringValue As String = TryCast(value, String)
If Not String.IsNullOrEmpty(stringValue) Then
Dim doubleValue As Double
If Double.TryParse(stringValue, doubleValue) Then
If doubleValue >= 0 AndAlso doubleValue <= 100 Then
Return New ValidationResult(True, Nothing)
End If
End If
End If
Return New ValidationResult(False, "Must be a number between 0 and 100")
End Function
End Class
End Namespace
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