DependencyProperty.IsValidValue(Object) Method

Definition

Namespace:

System.Windows

Assembly:

WindowsBase.dll

Determines whether the provided value is accepted for the type of property through basic type checking, and also potentially if it is within the allowed range of values for that type.

public:
 bool IsValidValue(System::Object ^ value);

public bool IsValidValue (object value);

member this.IsValidValue : obj -> bool

Public Function IsValidValue (value As Object) As Boolean

Parameters

value

Object

The value to check.

Returns

Boolean

true if the value is acceptable and is of the correct type or a derived type; otherwise, false.

Examples

The following example uses IsValidValue as a check before calling SetValue on the dependency property.

void TrySetValueWithValidate(DependencyObject target, DependencyProperty dp, object providedValue)
{
  if (dp.IsValidValue(providedValue))
  {
    target.SetValue(dp, providedValue);
  }
}

Private Sub TrySetValueWithValidate(ByVal target As DependencyObject, ByVal dp As DependencyProperty, ByVal providedValue As Object)
  If dp.IsValidValue(providedValue) Then
    target.SetValue(dp, providedValue)
  End If
End Sub

Remarks

For a dependency property, an allowed range of values for that type can be specified through a ValidateValueCallback that is provided in the dependency property registration.

This method calls IsValidType internally. If the dependency property in question has no ValidateValueCallback,then calling this method is effectively equivalent to calling IsValidType. If the dependency property does have a ValidateValueCallback, and if IsValidType would have returned true, then the value returned will be as implemented in the callback.

A null value is a valid value for reference type dependency properties, or for a Nullable<T> dependency property, and would return true for these cases. In cases where the dependency property is neither a reference nor a Nullable<T> type, IsValidType will return false for a null value rather than raise an exception.