TextBox validation

[Geysser]

I have a problem with validating a text field (and, being a WPF novice, please be gentle!)

My textbox is as follows:

<TextBox x:Name="PiecesSText" TextAlignment="Right"
                       Width="50" Height="18"
                       HorizontalAlignment="Left" VerticalAlignment="Top" 
                       Margin="42,129,0,0" Style="{StaticResource FlatTextBoxStyle}">
          <TextBox.Text>
               <Binding RelativeSource="{RelativeSource Self}"
                           Path="Text" UpdateSourceTrigger="PropertyChanged">
                    <Binding.ValidationRules>
                        <val:PieceNumValidator Min="1" Max="20"
                                                        ValidatesOnTargetUpdated="True" />
                    </Binding.ValidationRules
                </Binding>
          </TextBox.Text>
        </TextBox>

...and the validator is this:

Public Class PieceNumValidator : Inherits ValidationRule
    Public Property Min As Int16
    Public Property Max As Int16

    Public Overrides Function Validate(value As Object,
                                       cultureInfo As System.Globalization.CultureInfo) _
                                    As System.Windows.Controls.ValidationResult
      Dim iParam As Int16 = 0

      If value.ToString.Length <> 0 Then
        If IsNumeric(value) = True Then
          iParam = Int16.Parse(value.ToString)
        Else
          Return New ValidationResult(False, "Invalid data type!")
        End If
      Else
        Return New ValidationResult(False, "No data!")
      End If

      If iParam < Min Or iParam > Max Then
        Return New ValidationResult(False, "Param out of range!")
      Else
        Return New ValidationResult(True, Nothing)
      End If
    End Function
  End Class

When I type a number within the range, I get a StackOverflowException.
What could there be wrong?

 

[DangerRanger89]

can you provide the details of the Validationresult() method?

 

[Geysser]

Well, problem is solved now! That's what you get when you are a WinForms VB.NET'er and you try to run with WPF before you learn how to walk!
No RelativeSource={RelativeSource Self} anymore,just a nice Model binding neatly on the View Elements!