Visual Basic Reference

Visual Studio 6.0

CanPropertyChange Method

See Also    Example    Applies To

Asks the container if a property bound to a data source can have its value changed. The CanPropertyChange method is most useful if the property specified in PropertyName is bound to a data source.


object.CanPropertyChange PropertyName

The CanPropertyChange method syntax has these parts:

Part Description
object An object expression that evaluates to an object in the Applies To list.
PropertyName A string expression that represents a name of the property that the control is requesting to change.

Return values

The possible return values for CanPropertyChange are:

Setting Description
True The property specified in PropertyName can be changed at this time.
False The property specified in PropertyName cannot be changed at this time; the container has the bound data table open as read only. Do not set the property value; doing so may cause errors in some control containers.


The control should always call CanPropertyChange before changing the value of a property that can be data-bound.

Note   At present, CanPropertyChange always returns True in Visual Basic, even if the bound field is read-only in the data source. Visual Basic doesnt raise an error when the control attempts to change a read-only field; it just doesnt update the data source.

As an example, the following code shows how the CanPropertyChange method is used:

Public Property Let Address(ByVal cValue As String)
   If CanPropertyChange("Address") Then
      m_Address = cValue
      PropertyChanged "Address"
   End If
End Property