Creates and adds a DataColumn with the specified name and type to the columns collection.
[Visual Basic] Overloads Public Function Add( _ ByVal columnName As String, _ ByVal type As Type _ ) As DataColumn [C#] public DataColumn Add( string columnName, Type type ); [C++] public: DataColumn* Add( String* columnName, Type* type ); [JScript] public function Add( columnName : String, type : Type ) : 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). |
InvalidExpressionException | The column has a compute expression and it can't be bound. |
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.
If the collection is succesfully changed by adding or removing columns, the OnCollectionChanged event occurs.
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 cols = New DataSet1.Tables("Orders").Columns ' Add a new column and return it. myCol = cols.Add("Total", System.Type.GetType("System.Currency")) myCol.ReadOnly = True myCol.Unique = False End Sub
ColumnsCollection Class | ColumnsCollection Members | System.Data Namespace | ColumnsCollection.Add Overload List | ColumnName | DataType | Expression