Creates and adds a DataColumn with the specified name to the columns collection.
[Visual Basic] Overloads Public Function Add( _ ByVal columnName As String _ ) As DataColumn [C#] public DataColumn Add( string columnName ); [C++] public: DataColumn* Add( String* columnName ); [JScript] public function Add( columnName : String ) : DataColumn;
The newly created DataColumn.
Exception Type | Condition |
---|---|
DuplicateNameException | The collection already has a column with the same name (the comparison is not case-sensitive). |
By default, the column's DataType is string.
If a null reference (in Visual Basic Nothing) or an empty string ("") is passed in for the name, a default name ("Column1", "Column2", etc.) is given to the column.
The Contains method determine whether a column with the proposed name already exists in the collection.
The following example creates and adds a new DataColumn to a ColumnsCollection of a DataTable.
[Visual Basic]
Private Sub AddColumn() Dim cols As ColumnsCollection Dim myCol As DataColumn ' Get the ColumnsCollection from a table in a DataSet. cols = New DataSet1.Tables("Prices").Columns myCol = cols.Add("Total") With myCol .DataType = System.Type.GetType("System.Currency") .ReadOnly = True .Expression = "UnitPrice * Quantity" .Unique = False End With End Sub
ColumnsCollection Class | ColumnsCollection Members | System.Data Namespace | ColumnsCollection.Add Overload List | ColumnName | Contains | DataType | Expression