DataColumnCollection.Add Method (DataColumn)

Creates and adds the specified DataColumn object to the DataColumnCollection.

Namespace: System.Data
Assembly: System.Data (in

public void Add (
	DataColumn column
public void Add (
	DataColumn column
public function Add (
	column : DataColumn



The DataColumn to add.

Exception typeCondition


The column parameter is a null reference (Nothing in Visual Basic).


The column already belongs to this collection, or to another collection.


The collection already has a column with the specified name. (The comparison is not case-sensitive.)


The expression is invalid. See the Expression property for more information about how to create expressions.

If the collection is successfully changed by adding or removing columns, the CollectionChanged event occurs.

The following example adds a DataColumn to a DataColumnCollection.

Private Sub AddDataColumn()
    ' Get the DataColumnCollection from a DataTable in a DataSet.
    Dim columns As DataColumnCollection = _
    Dim column As DataColumn = New DataColumn
    With column
       .DataType = System.Type.GetType("System.Decimal")
       .ColumnName = "ItemPrice"
       .Caption = "Price"
       .ReadOnly = False
       .Unique = False
       .DefaultValue = 0
    End With
End Sub

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 2.0, 1.0