ValidationStep 列舉


指定 ValidationRule 執行的時機。Specifies when a ValidationRule runs.

public enum class ValidationStep
public enum ValidationStep
type ValidationStep = 
Public Enum ValidationStep


CommittedValue 3

會於值認可到來源後執行 ValidationRuleRuns the ValidationRule after the value has been committed to the source.

ConvertedProposedValue 1

會於值轉換後執行 ValidationRuleRuns the ValidationRule after the value is converted.

RawProposedValue 0

會在任何轉換發生之前執行 ValidationRuleRuns the ValidationRule before any conversion occurs.

UpdatedValue 2

會在來源更新之後執行 ValidationRuleRuns the ValidationRule after the source is updated.


下列範例會使用名為ValidateDateAndPrice的驗證規則。The following example uses a validation rule named ValidateDateAndPrice. ValidationRule.ValidationStep規則的設定為ConvertedProposedValue , 因此ValidationRule.Validate當它執行時, 方法可以存取來源屬性類型的值。The ValidationRule.ValidationStep for this rule is set to ConvertedProposedValue so that when it runs, the ValidationRule.Validate method has access to values that are of the source property's type.

RawProposedValue ValidationRule.ValidationStep ValidationRule.Validate當和規則FutureDateRule執行時, 每個方法中的值都是字串, 因為的預設值是。 PriceIsAPositiveNumberWhen the PriceIsAPositiveNumber and FutureDateRule rules run, the values in each ValidationRule.Validate method are strings because the default value of ValidationRule.ValidationStep is RawProposedValue. 因此, 這些規則會在值轉換成其各自的類型之前執行。Therefore, the rules run before the values are converted to their respective types.

<StackPanel Name="stackPanel1"  Margin="10" Width="250"

    <Style TargetType="HeaderedContentControl">
      <Setter Property="Margin" Value="2"/>
      <Setter Property="Focusable" Value="False"/>
      <Setter Property="Template">
          <ControlTemplate TargetType="HeaderedContentControl">
            <DockPanel LastChildFill="False">
              <ContentPresenter ContentSource="Header" DockPanel.Dock="Left" Focusable="False" VerticalAlignment="Center"/>
              <ContentPresenter ContentSource="Content" Margin="5,0,0,0" DockPanel.Dock="Right" VerticalAlignment="Center"/>


    <Style TargetType="Button">
      <Setter Property="Width" Value="100"/>
      <Setter Property="Margin" Value="10,15,15,15"/>


    <BindingGroup NotifyOnValidationError="True">
        <src:ValidateDateAndPrice ValidationStep="ConvertedProposedValue" />
  <TextBlock FontSize="14" Text="Enter an item for sale"/>
  <HeaderedContentControl Header="Description">
    <TextBox Width="150" Text="{Binding Path=Description, Mode=TwoWay}"/>
  <HeaderedContentControl Header="Price">
    <TextBox Name="priceField"  Width="150">
        <Binding Path="Price" Mode="TwoWay" >
  <HeaderedContentControl Header="Date Offer Ends">
    <TextBox Name="dateField" Width="150" >
        <Binding Path="OfferExpires" StringFormat="d" >
  <StackPanel Orientation="Horizontal">
    <Button IsDefault="True" Click="Submit_Click">_Submit</Button>
    <Button IsCancel="True" Click="Cancel_Click">_Cancel</Button>
  <HeaderedContentControl Header="Description">
    <TextBlock Width="150" Text="{Binding Path=Description}"/>
  <HeaderedContentControl Header="Price">
    <TextBlock Width="150" Text="{Binding Path=Price, StringFormat=c}"/>
  <HeaderedContentControl Header="Date Offer Ends">
    <TextBlock Width="150" Text="{Binding Path=OfferExpires, StringFormat=d}"/>

下列範例會顯示ValidateDateAndPrice驗證規則。The following example shows the ValidateDateAndPrice validation rule. Price Double在方法中, 屬性DateTime的類型為,而屬性的類型為。OfferExpires ValidationRule.ValidateIn the ValidationRule.Validate method, the Price property is of type Double, and the OfferExpires property is of type DateTime. ValidationRule執行時, 字串已轉換成其各自的類型。The strings have been converted to their respective types by the time the ValidationRule runs.

public class ValidateDateAndPrice : ValidationRule
    // Ensure that an item over $100 is available for at least 7 days.
    public override ValidationResult Validate(object value, CultureInfo cultureInfo)
        BindingGroup bg = value as BindingGroup;

        // Get the source object.
        PurchaseItem item = bg.Items[0] as PurchaseItem;
        object doubleValue;
        object dateTimeValue;

        // Get the proposed values for Price and OfferExpires.
        bool priceResult = bg.TryGetValue(item, "Price", out doubleValue);
        bool dateResult = bg.TryGetValue(item, "OfferExpires", out dateTimeValue);

        if (!priceResult || !dateResult)
            return new ValidationResult(false, "Properties not found");

        double price = (double)doubleValue;
        DateTime offerExpires = (DateTime)dateTimeValue;

        // Check that an item over $100 is available for at least 7 days.
        if (price > 100)
            if (offerExpires < DateTime.Today + new TimeSpan(7, 0, 0, 0))
                return new ValidationResult(false, "Items over $100 must be available for at least 7 days.");

        return ValidationResult.ValidResult;
Public Class ValidateDateAndPrice
    Inherits ValidationRule
    ' Ensure that an item over $100 is available for at least 7 days.
    Public Overrides Function Validate(ByVal value As Object, ByVal cultureInfo As CultureInfo) As ValidationResult
        Dim bg As BindingGroup = TryCast(value, BindingGroup)

        ' Get the source object.
        Dim item As PurchaseItem = TryCast(bg.Items(0), PurchaseItem)

        Dim doubleValue As Object = Nothing
        Dim dateTimeValue As Object = Nothing

        ' Get the proposed values for Price and OfferExpires.
        Dim priceResult As Boolean = bg.TryGetValue(item, "Price", doubleValue)
        Dim dateResult As Boolean = bg.TryGetValue(item, "OfferExpires", dateTimeValue)

        If (Not priceResult) OrElse (Not dateResult) Then
            Return New ValidationResult(False, "Properties not found")
        End If

        Dim price As Double = CDbl(doubleValue)
        Dim offerExpires As Date = CDate(dateTimeValue)

        ' Check that an item over $100 is available for at least 7 days.
        If price > 100 Then
            If offerExpires < Date.Today + New TimeSpan(7, 0, 0, 0) Then
                Return New ValidationResult(False, "Items over $100 must be available for at least 7 days.")
            End If
        End If

        Return ValidationResult.ValidResult

    End Function
End Class