Checks if a given column can be removed from the collection.
[Visual Basic] Public Function CanRemove( _ ByVal column As DataColumn _ ) As Boolean [C#] public bool CanRemove( DataColumn column ); [C++] public: bool CanRemove( DataColumn* column ); [JScript] public function CanRemove( column : DataColumn ) : Boolean;
true if no exception occurs and the column can be removed; otherwise, false.
Exception Type | Condition |
---|---|
ArgumentNullException | The column parameter is a null reference (in Visual Basic Nothing). |
ArgumentException | The column doesn't belong to this collection.
-Or- The column is part of a relationship. -Or- Another column's compute expression depends on this column. |
The CanRemove method performs several checks before returning a true or false including the following: whether the column exists, belongs to the table, is involved in a constraint or relation.
Use the CanRemove method before attempting to remove any column from a collection. You can also use the Contains method to determine if a particular column exists before attempting to reference it.
The following example first uses the Contains method to determine if a particular column is found in the collection. If found, the CanRemove method tests whether the column can be removed. If so, the column is removed with the Remove method.
[Visual Basic]
Dim cols As ColumnsCollection ' Get the ColumnsCollection from a DataTable in a DataSet. cols = DataSet1.Tables("Orders").Columns If cols.Contains(2) Then If cols.CanRemove(cols(2)) Then cols.Remove 2 End If End If
ColumnsCollection Class | ColumnsCollection Members | System.Data Namespace | Contains | Remove