DataColumnCollection.CanRemove(DataColumn) Method
Definition
Important
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Checks whether a specific column can be removed from the collection.
public:
bool CanRemove(System::Data::DataColumn ^ column);public bool CanRemove(System.Data.DataColumn? column);public bool CanRemove(System.Data.DataColumn column);member this.CanRemove : System.Data.DataColumn -> boolPublic Function CanRemove (column As DataColumn) As BooleanParameters
- column
- DataColumn
A DataColumn in the collection.
Returns
true if the column can be removed. false if,
The
columnparameter isnull.The column does not belong to this collection.
The column is part of a relationship.
Another column's expression depends on this column.
Exceptions
The column parameter is null.
The column does not belong to this collection.
-or-
The column is part of a relationship.
-or-
Another column's expression depends on this column.
Examples
The following example first uses the Contains method to determine whether 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.
private void RemoveColumn(string columnName, DataTable table)
{
DataColumnCollection columns = table.Columns;
if (columns.Contains(columnName))
if (columns.CanRemove(columns[columnName]))
columns.Remove(columnName);
}
Private Sub RemoveColumn( _
columnName As String, table As DataTable)
Dim columns As DataColumnCollection = table.Columns
If columns.Contains(columnName) Then
If columns.CanRemove(columns(columnName)) Then
columns.Remove(columnName)
End If
End If
End Sub
Remarks
The CanRemove method performs several checks before returning a true or false result. This includes the following: whether the column exists, belongs to the table, or is involved in a constraint or relation.
Use the CanRemove method before you try to remove any column from a collection. You can also use the Contains method to determine whether a particular column exists before you try to remove it.
