ColumnAttribute.CanBeNull Property

Reference

Definition

Namespace:: System.Data.Linq.Mapping

Assembly:: System.Data.Linq.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Gets or sets whether a column can contain null values.

public:
 property bool CanBeNull { bool get(); void set(bool value); };

public bool CanBeNull { get; set; }

member this.CanBeNull : bool with get, set

Public Property CanBeNull As Boolean

Property Value

Boolean

Default = true.

Examples

[Column(Storage="_LastName", DbType="NVarChar(20) NOT NULL", CanBeNull=false)]
public string LastName
{
    get
    {
        return this._LastName;
    }
    set
    {
        if ((this._LastName != value))
        {
            this.OnLastNameChanging(value);
            this.SendPropertyChanging();
            this._LastName = value;
            this.SendPropertyChanged("LastName");
            this.OnLastNameChanged();
        }
    }
}

<Column(Storage:="_LastName", DbType:="NVarChar(20) NOT NULL", CanBeNull:=false)>  _
Public Property LastName() As String
    Get
        Return Me._LastName
    End Get
    Set
        If ((Me._LastName = value)  _
                    = false) Then
            Me.OnLastNameChanging(value)
            Me.SendPropertyChanging
            Me._LastName = value
            Me.SendPropertyChanged("LastName")
            Me.OnLastNameChanged
        End If
    End Set
End Property

Remarks

If you set this value to false, the data in the corresponding column is assumed to be non-null.

Note

This property is duplicated from the DbType property for convenience. The CreateDatabase method uses only the DbType property. For this reason, you must specify whether a column can contain null values in the DbType property also.

Applies to

Jaa