A default value is the value that is automatically assigned to the column when a DataRow is created (for example, the date and time when the DataRow was created.

When AutoIncrement is set to true, there can be no default value.

You can create a new row using the ItemArray property of the DataRow class and passing the method an array of values. This is a potential problem for a column with a default value because its value is generated automatically. To use the ItemArray property with such a column, place nullNothingnullptra null reference (Nothing in Visual Basic) in the column's position in the array. For more information, see the ItemArray property.

The following example creates several DataColumn objects that have different data types, and sets appropriate default values to each column.

Private Sub CreateColumns()
    Dim column As DataColumn
    Dim table As New DataTable

    column = New DataColumn
    With column
       .DataType = System.Type.GetType("System.String")
       .DefaultValue = "Address"
       .Unique = False
    End With
    table.Columns.Add(column)

    column = New DataColumn
    With column
       .DataType = System.Type.GetType("System.Int32")
       .DefaultValue = 100
    End With
    table.Columns.Add(column)

    column = New DataColumn
    With column
       .DataType = System.Type.GetType("System.DateTime")
       .DefaultValue = "1/1/2001"
    End With
    table.Columns.Add(column)

    Dim row As DataRow
    ' Add one row. Since it has default values, 
    ' no need to set values yet.
    row = table.NewRow

    table.Rows.Add(row)
 End Sub

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

.NET Framework

.NET Compact Framework

XNA Framework

Reference

Other Resources