How do I get the Validation Error Template and Validation Rules working for one of my textbox?

See more:

validation

Hi there, I'm new to working in WPF using VB.NET. Currently faced with a problem where the validation error template isn't working and on top of that my validation rules is awry where it keeps looping. Would appreciate if any kind soul could help me see where I missed out.

The following codes are from my application.xaml, Validation Class and the actual form Sponsor.xaml

<Style x:Key="textboxerror" TargetType="{x:Type TextBox}" >
            <Style.Triggers>
                <Trigger Property="Validation.HasError" Value="True">
                    <Setter Property="ToolTip" Value="{Binding RelativeSource={RelativeSource Self}, 
                                Path=(Validation.Errors)[0].ErrorContent}"/>
                </Trigger>
            </Style.Triggers>
            <Setter Property="Validation.ErrorTemplate" Value="{StaticResource TextBoxError }"/>
            <Setter Property="Width" Value="265" />
            <Setter Property="Height" Value="25" />
            <Setter Property="Margin" Value="135,250,0,0" />
            <Setter Property="HorizontalAlignment" Value="Left"/>
            <Setter Property="HorizontalContentAlignment" Value="Left"/>
            <Setter Property="VerticalAlignment" Value="Top" />
            <Setter Property="VerticalContentAlignment" Value="Center"/>            
            <Setter Property="Background" Value="#FFFFFFFF"/>
            <Setter Property="Foreground" Value="#FFB4B4B4"/>
            <Setter Property="FontFamily" Value="Arial"/>
            <Setter Property="FontSize" Value="14" />
            <Setter Property="TextWrapping" Value="Wrap" />
            <Setter Property="FontStyle" Value="Italic" />
        </Style>

        <ControlTemplate x:Key="TextBoxError" TargetType="{x:Type TextBox}" >
            <DockPanel>
                <AdornedElementPlaceholder 
           x:Name="ErrorAdorner"
        ></AdornedElementPlaceholder>
                <TextBlock Foreground="Red" FontSize="12"
            DockPanel.Dock="Top">!</TextBlock>
            </DockPanel>
        </ControlTemplate>

Next is my Validation Class.vb:-

Imports System.Globalization
Imports System.Windows.Controls
Imports System.Windows.Data
Imports System.ComponentModel

Namespace Validation

    Public Class ValidateDntAmt

        Inherits ValidationRule

        Public Overrides Function Validate(ByVal value As Object, ByVal cultureInfo As CultureInfo) As Controls.ValidationResult

            Dim strText As String = value

            If strText = "" Or strText = "0" Then

                Dim Message1 As String = "The donation amount cannot be nothing."
                Dim Caption1 As String = "Error Detected in Input"

                MessageBox.Show(Message1, Caption1, MessageBoxButton.OK, MessageBoxImage.Exclamation)

                Return New ValidationResult(False, "The donation amount cannot be nothing.")

            Else

                Return New ValidationResult(True, Nothing)

            End If

        End Function

    End Class

And my Sponsor.xaml:-

<window x:class="Sponsor" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:ASC2016"   
        xmlns:validators="clr-namespace:ASC2016.Validation"
        mc:Ignorable="d"
        Title="Sponsor" Height="600" Width="800" MaxHeight="600" MaxWidth="800" FontFamily="Arial" WindowStartupLocation="CenterScreen" Icon="Icons/Icon3.ico" Initialized="Window_Initialized" Loaded="Window_Loaded">
    <window.resources>


    </window.resources>
    <grid>
         <textbox x:name="txtBoxDntAmt" style="{StaticResource textBoxStyle}" width="70" margin="620,430,0,0">
                 Validation.ErrorTemplate="{StaticResource TextBoxError}">
            <textbox.text>
                <binding elementname="txtBoxDntAmt" path="Text" mode="TwoWay" updatesourcetrigger="PropertyChanged">
                    <binding.validationrules>
                        <validators:validatedntamt ></validators:validatedntamt>
                    </binding.validationrules>
                </binding>
            </textbox.text>
        </textbox>

    </grid>
  </window>