How to: Specify Which Members are Tested for Concurrency Conflicts

Apply one of three enums to the LINQ to SQL UpdateCheck property on a ColumnAttribute attribute to specify which members are to be included in update checks for the detection of optimistic concurrency conflicts.

The UpdateCheck property (mapped at design time) is used together with run-time concurrency features in LINQ to SQL. For more information, see Optimistic Concurrency: Overview.

For code examples, see UpdateCheck.

1. Add the UpdateCheck property to the ColumnAttribute attribute.

2. Set the UpdateCheck property value to Always.

1. Add the UpdateCheck property to the ColumnAttribute attribute.

2. Set the UpdateCheck property value to Never.

1. Add the UpdateCheck property to the ColumnAttribute attribute.

2. Set the UpdateCheck property value to WhenChanged.

The following example specifies that HomePage objects should never be tested during update checks. For more information, see UpdateCheck.

[Column(Storage="_HomePage", DbType="NText", UpdateCheck=UpdateCheck.Never)]
public string HomePage
{
    get
    {
        return this._HomePage;
    }
    set
    {
        if ((this._HomePage != value))
    {
        this.OnHomePageChanging(value);
        this.SendPropertyChanging();
            this._HomePage = value;
        this.SendPropertyChanged("HomePage");
            this.OnHomePageChanged();
    }
    }
}

<Column(Storage:="_HomePage", DbType:="NText", UpdateCheck:=UpdateCheck.Never)>  _
Public Property HomePage() As String
    Get
        Return Me._HomePage
    End Get
    Set(ByVal value As String)
        If ((Me._HomePage <> value)  _
            = false) Then
        Me.OnHomePageChanging(value)
            Me.SendPropertyChanging
            Me._HomePage = value
            Me.SendPropertyChanged("HomePage")
            Me.OnHomePageChanged
        End If
    End Set
End Property

• How to: Manage Change Conflicts
• Making and Submitting Data Changes