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.NET Framework Class Library
ValidationStep Enumeration

Specifies when a ValidationRule runs.

Namespace:   System.Windows.Controls
Assembly:  PresentationFramework (in PresentationFramework.dll)
Syntax
Public Enumeration ValidationStep
public enum ValidationStep
public enum class ValidationStep
type ValidationStep
public enum ValidationStep
<object property="enumerationMemberName" .../>
Members
Member nameDescription
CommittedValueRuns the ValidationRule after the value has been committed to the source.
ConvertedProposedValueRuns the ValidationRule after the value is converted.
RawProposedValueRuns the ValidationRule before any conversion occurs.
UpdatedValueRuns the ValidationRule after the source is updated.
Examples

The following example uses a ValidationRule named ValidateDateAndPrice. The ValidationStep for this rule is set to ConvertedProposedValue so that when it runs, the Validate method has access to values that are of the source property's type.

When the PriceIsAPositiveNumber and FutureDateRule rules run, the values in each Validate method are strings because the default value of ValidationStep is RawProposedValue. Therefore, the rules run before the values are converted to their respective types.

<StackPanel Name="stackPanel1"  Margin="10" Width="250"
            Loaded="stackPanel1_Loaded"
            Validation.Error="ItemError">

  <StackPanel.Resources>
    <Style TargetType="HeaderedContentControl">
      <Setter Property="Margin" Value="2"/>
      <Setter Property="Focusable" Value="False"/>
      <Setter Property="Template">
        <Setter.Value>
          <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"/>
            </DockPanel>

          </ControlTemplate>
        </Setter.Value>
      </Setter>
    </Style>

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

    </Style>

  </StackPanel.Resources>

  <StackPanel.BindingGroup>
    <BindingGroup NotifyOnValidationError="True">
      <BindingGroup.ValidationRules>
        <src:ValidateDateAndPrice ValidationStep="ConvertedProposedValue" />
      </BindingGroup.ValidationRules>
    </BindingGroup>
  </StackPanel.BindingGroup>

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

The following example shows the ValidateDateAndPrice ValidationRule. In the Validate method, the Price property is of type Double and the OfferExpires property is of type DateTime. The strings have been converted to their respective types by the time the ValidationRule runs.

	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
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;

    }
}
Version Information

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5 SP1, 3.0 SP2

.NET Framework Client Profile

Supported in: 4, 3.5 SP1