Question

我想验证一些控件，但只有选中了我的复选框。（在此示例中，我只显示一个要验证的文本框）

我尝试使用BindingGroup，但这意味着该复选框也经过验证，这会给我错误的结果。

现在我尝试使用MultiBinding：

<CheckBox Name="chkUseLqv"
              Grid.Row="6"
              Grid.Column="0"
              Margin="0,0,8,0"
              HorizontalAlignment="Right"
              VerticalAlignment="Center"
              Content="Use LQV"
              IsChecked="{Binding LqvConfigurationEnabled}" />

[...]

<GroupBox Grid.Row="1"
          Grid.RowSpan="6"
          Grid.Column="4"
          Margin="5"
          Header="LQV Configuration"
          IsEnabled="{Binding LqvConfigurationEnabled}">
  <Grid>
    <TextBox Name="txtLqvDatabaseServer"
             Grid.Row="1"
             Grid.Column="1"
             VerticalAlignment="Center"
             Validation.ErrorTemplate="{StaticResource ValidationErrorTemplate}">
      <TextBox.Text>
        <MultiBinding Converter="{Converters:LqvConfigurationMultiBindingConverter}" UpdateSourceTrigger="PropertyChanged">
          <MultiBinding.ValidationRules>
            <LocalValidationRules:LqvDatabaseServerValidator />
          </MultiBinding.ValidationRules>
          <Binding ElementName="chkUseLqv" Path="IsChecked" />
          <Binding Path="LqvDatabaseServer" />
        </MultiBinding>
      </TextBox.Text>
    </TextBox>
  </Grid>
</GroupBox>

我的验证员：

Imports System.Text.RegularExpressions

Namespace ValidationRules
  Public Class LqvDatabaseServerValidator
    Inherits ValidationRule

    Public Overrides Function Validate(ByVal value As Object, ByVal cultureInfo As System.Globalization.CultureInfo) As System.Windows.Controls.ValidationResult
      Dim useLqv = CType(value, Object()).OfType(Of Boolean).First()
      Dim valueFromSource = CType(value, Object()).OfType(Of String).FirstOrDefault()

      If useLqv Then
        If String.IsNullOrEmpty(valueFromSource) Then
          Return New ValidationResult(False, "This field is required!")
        End If

        If Not (
          Regex.IsMatch(valueFromSource, "^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$") OrElse
          Regex.IsMatch(valueFromSource, "^(([a-zA-Z]|[a-zA-Z][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z]|[A-Za-z][A-Za-z0-9\-]*[A-Za-z0-9])$")
          ) Then
          Return New ValidationResult(False, "Invalid input!")
        End If
      End If

      Return ValidationResult.ValidResult
    End Function
  End Class
End Namespace

转换器：

Imports System.Windows.Markup

Namespace Converters
  Public Class LqvConfigurationMultiBindingConverter
    Inherits MarkupExtension
    Implements IMultiValueConverter

    Public Sub New()
    End Sub

    Private _orig As Object()

    Public Function Convert(ByVal values() As Object, ByVal targetType As System.Type, ByVal parameter As Object, ByVal culture As System.Globalization.CultureInfo) As Object Implements System.Windows.Data.IMultiValueConverter.Convert
      _orig = values
      Return values.OfType(Of String).FirstOrDefault()
    End Function

    Public Function ConvertBack(ByVal value As Object, ByVal targetTypes() As System.Type, ByVal parameter As Object, ByVal culture As System.Globalization.CultureInfo) As Object() Implements System.Windows.Data.IMultiValueConverter.ConvertBack
      Return _orig
    End Function

    Public Overrides Function ProvideValue(ByVal serviceProvider As System.IServiceProvider) As Object
      Return New LqvConfigurationMultiBindingConverter()
    End Function
  End Class
End Namespace

但它不起作用。你能救我吗？

Answer 1

我是这样做的：

在资源中定义样式：

<Style x:Key="lqvDependingFields" TargetType="{x:Type TextBox}">
    <Setter Property="Validation.ErrorTemplate">
      <Setter.Value>
        <ControlTemplate />
      </Setter.Value>
    </Setter>
    <Style.Triggers>
      <DataTrigger Binding="{Binding ElementName=chkUseLqv, Path=IsChecked}" Value="true">
        <Setter Property="Validation.ErrorTemplate" Value="{StaticResource ValidationErrorTemplate}" />
      </DataTrigger>
    </Style.Triggers>
  </Style>

有一个复选框：

<CheckBox Name="chkUseLqv"
          Grid.Row="6"
          Grid.Column="0"
          Margin="0,0,8,0"
          HorizontalAlignment="Right"
          VerticalAlignment="Center"
          Content="Use LQV"
          IsChecked="{Binding LqvConfigurationEnabled}" />

使用控件上的样式：

    <TextBox Name="txtLqvDatabaseServer"
             Grid.Row="1"
             Grid.Column="1"
             VerticalAlignment="Center"
             DependencyProperties:AttachedWindowProperties.HasValidationError="{Binding LqvDatabaseServerValidationError}"
             Style="{StaticResource lqvDependingFields}">
      <TextBox.Text>
        <Binding NotifyOnSourceUpdated="True"
                 Path="LqvDatabaseServer"
                 UpdateSourceTrigger="PropertyChanged">
          <Binding.ValidationRules>
            <LocalValidationRules:LqvDatabaseServerValidator ValidatesOnTargetUpdated="True" />
          </Binding.ValidationRules>
        </Binding>
      </TextBox.Text>
    </TextBox>

依赖属性：

#Region "HasValidationErrorProperty"

    Public Shared ReadOnly HasValidationErrorProperty As DependencyProperty =
      DependencyProperty.RegisterAttached("HasValidationError", GetType(Boolean), GetType(AttachedWindowProperties),
                                          New FrameworkPropertyMetadata(False, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
                                                                        Nothing, AddressOf CoerceHasValidationError))

    Public Shared Function GetHasValidationError(ByVal d As DependencyObject) As Boolean
      Return CBool(d.GetValue(HasValidationErrorProperty))
    End Function

    Public Shared Sub SetHasValidationError(ByVal d As DependencyObject, ByVal value As Boolean)
      d.SetValue(HasValidationErrorProperty, value)
    End Sub

    Private Shared Function CoerceHasValidationError(ByVal d As DependencyObject, ByVal baseValue As Object) As Object
      Dim result As Boolean = CBool(baseValue)

      If BindingOperations.IsDataBound(d, HasValidationErrorProperty) Then
        If GetHasErrorDescriptor(d) Is Nothing Then
          Dim desc = DependencyPropertyDescriptor.FromProperty(Validation.HasErrorProperty, d.GetType)
          desc.AddValueChanged(d, AddressOf OnHasErrorChanged)
          SetHasErrorDescriptor(d, desc)
          result = Validation.GetHasError(d)
        End If
      Else
        If GetHasErrorDescriptor(d) IsNot Nothing Then
          Dim desc As DependencyPropertyDescriptor = GetHasErrorDescriptor(d)
          desc.RemoveValueChanged(d, AddressOf OnHasErrorChanged)
          SetHasErrorDescriptor(d, Nothing)
        End If
      End If

      Return result
    End Function

    Private Shared Sub OnHasErrorChanged(ByVal sender As Object, ByVal e As EventArgs)
      Dim d As DependencyObject = TryCast(sender, DependencyObject)

      If d IsNot Nothing Then
        d.SetValue(HasValidationErrorProperty, d.GetValue(Validation.HasErrorProperty))
      End If
    End Sub

    Private Shared ReadOnly HasErrorDescriptorProperty As DependencyProperty =
      DependencyProperty.RegisterAttached("HasErrorDescriptor", GetType(DependencyPropertyDescriptor), GetType(AttachedWindowProperties))

    Private Shared Function GetHasErrorDescriptor(ByVal d As DependencyObject) As DependencyPropertyDescriptor
      Return CType(d.GetValue(HasErrorDescriptorProperty), DependencyPropertyDescriptor)
    End Function

    Private Shared Sub SetHasErrorDescriptor(ByVal d As DependencyObject, ByVal value As DependencyPropertyDescriptor)
      d.SetValue(HasErrorDescriptorProperty, value)
    End Sub

#End Region

LqvDatabaseServer和LqvDatabaseServerValidationErrors是我的ViewModel中的属性。

如果选中复选框，则启用ValidationRule

1 个答案: