Initializes a new instance of the DataColumn class using the specified name, data type, and expression.
[Visual Basic] Overloads Public Sub New( _ ByVal columnName As String, _ ByVal dataType As Type, _ ByVal expr As String _ ) [C#] public DataColumn( string columnName, Type dataType, string expr ); [C++] public: DataColumn( String* columnName, Type* dataType, String* expr ); [JScript] public function DataColumn( columnName : String, dataType : Type, expr : String );
Exception Type | Condition |
---|---|
ArgumentNullException | No dataType was specified. |
The following example creates a computed column.
[Visual Basic]
Private Sub AddDataColumn() Dim myColumn As DataColumn Dim dt As System.Type dt = New System.Type.GetType("System.Currency") myColumn = New DataColumn("Tax", dt, "UnitPrice * .0862") ' Set various properties. With myColumn .Unique = False .AutoIncrement = False .ReadOnly = True End With ' Add to Columns collection. myTable.Columns.Add myColumn End Sub
DataColumn Class | DataColumn Members | System.Data Namespace | DataColumn Constructor Overload List | DefaultValue | ColumnName | Caption | DataTable | DataType | Expression