BindingGroup.ValidationRules Property

Definition

Namespace:

System.Windows.Data

Assembly:

PresentationFramework.dll

Gets a collection of ValidationRule objects that validate the source objects in the BindingGroup.

public:
 property System::Collections::ObjectModel::Collection<System::Windows::Controls::ValidationRule ^> ^ ValidationRules { System::Collections::ObjectModel::Collection<System::Windows::Controls::ValidationRule ^> ^ get(); };

public System.Collections.ObjectModel.Collection<System.Windows.Controls.ValidationRule> ValidationRules { get; }

member this.ValidationRules : System.Collections.ObjectModel.Collection<System.Windows.Controls.ValidationRule>

Public ReadOnly Property ValidationRules As Collection(Of ValidationRule)

Property Value

Collection<ValidationRule>

A collection of ValidationRule objects that validate the source objects in the BindingGroup.

Examples

The following example adds the custom ValidationRule, ValidateDateAndPrice, to the BindingGroup.

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

The following example shows the ValidateDateAndPrice class. The Validate method uses the BindingGroup to get the values the user entered into the form, and checks that if an item is over 100 dollars, it will be available for at least seven days.

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

Remarks

When a ValidationRule is added to a BindingGroup, the BindingGroup is passed in as the first parameter of the Validate method. You can get the proposed values of the object by using the TryGetValue or GetValue(Object, String) method. You can get the objects that are the sources of the bindings from the Items property.