Use Reset and ShouldSerialize to control a property (Windows Forms .NET)

In this article, you learn how to create the Reset<PropertyName> and ShouldSerialize<PropertyName> methods to manage a property for the Properties window in Visual Studio. Reset and ShouldSerialize are optional methods that you can provide for a property, if the property doesn't have a simple default value. If the property has a simple default value, you should apply the DefaultValueAttribute and supply the default value to the attribute class constructor instead. Either of these mechanisms enables the following features in the designer:

• The property provides visual indication in the property browser if it has been modified from its default value.
• The user can right-click on the property and choose Reset to restore the property to its default value.
• The designer generates more efficient code.

For more information about properties, see Reset and ShouldSerialize.

Supporting code

This article demonstrates the Reset and ShouldSerialize methods by creating a compass rose control. If you're working with your own user control, you can skip this section.

1. Add the following enumeration to your code:

   public enum Directions
   {
       None,
       North,
       NorthEast,
       East,
       SouthEast,
       South,
       SouthWest,
       West,
       NorthWest,
   }
   

   Public Enum Directions
       None
       North
       NorthEast
       East
       SouthEast
       South
       SouthWest
       West
       NorthWest
   End Enum
   

2. Add a user control named CompassRose.

3. Add a property named Direction of type Directions to the user control.

   public Directions Direction { get; set; } = Directions.None;
   

   Public Property Direction As Directions = Directions.None
   

Reset

The Reset<PropertyName> method resets the corresponding <PropertyName> property to its default value.

The following code resets the Direction property to None, which is considered the default value for the compass rose control:

private void ResetDirection() =>
    Direction = Directions.None;

Private Sub ResetDirection()
    Direction = Directions.None
End Sub

ShouldSerialize

The ShouldSerialize<PropertyName> method returns a boolean value that indicates whether or not the backing property has changed from its default value and should be serialized into the designer's code.

The following code returns true when the Direction property doesn't equal None, indicating that a direction has been chosen:

private bool ShouldSerializeDirection() =>
    Direction != Directions.None;

Private Function ShouldSerializeDirection() As Boolean
    Return Direction <> Directions.None
End Function

Example

The following code shows the Reset and ShouldSerialize methods for the Direction property:

public partial class CompassRose : UserControl
{
    public Directions Direction { get; set; } = Directions.None;

    public CompassRose() =>
        InitializeComponent();

    private void ResetDirection() =>
        Direction = Directions.None;

    private bool ShouldSerializeDirection() =>
        Direction != Directions.None;
}

Public Class CompassRose

    Public Property Direction As Directions = Directions.None

    Private Sub ResetDirection()
        Direction = Directions.None
    End Sub

    Private Function ShouldSerializeDirection() As Boolean
        Return Direction <> Directions.None
    End Function

End Class