Initializes a new instance of the ForeignKeyConstraint class with the specified parent and child DataColumn objects.
[Visual Basic] Overloads Public Sub New( _ ByVal parentColumn As DataColumn, _ ByVal childColumn As DataColumn _ ) [C#] public ForeignKeyConstraint( DataColumn parentColumn, DataColumn childColumn ); [C++] public: ForeignKeyConstraint( DataColumn* parentColumn, DataColumn* childColumn ); [JScript] public function ForeignKeyConstraint( parentColumn : DataColumn, childColumn : DataColumn );
Exception Type | Condition |
---|---|
ArgumentNullException | One or both of the columns is a null reference (in Visual Basic Nothing). |
InvalidConstraintException | The columns have different data types.
-Or- The tables don't belong to the same DataSet. |
The following example creates a new ForeignKeyConstraint, sets various of its properties, and adds it to a DataTable object's ConstraintsCollection.
[Visual Basic]
' The next line goes into the Declarations section of the module: ' SuppliersProducts is a class derived from DataSet. Private myDataSet As SuppliersProducts Private Sub CreateConstraint() ' Declare parent column and child column variables. Dim pCol As DataColumn Dim cCol As DataColumn Dim myFKC As ForeignKeyConstraint ' Set parent and child column variables. pCol = MyDataSet.Tables("Suppliers").Columns("SupplierID") cCol = MyDataSet.Tables("Products").Columns("SupplieriD") myFKC = New ForeignKeyConstraint(pCol, cCol) ' Set various properties of the constraint. With myFKC .RelationName = "SuppierFKConstraint" .DeleteRule = Rule.SetNull .UpdateRule = Rule.Cascade .AcceptRejectRule = AcceptRejectRule.Cascade End With ' Add the constraint, and set EnforceConstraints to true. myDataSet.Tables("Suppliers").Constraints.Add myFKC myDataSet.EnforceConstraints = True End Sub
ForeignKeyConstraint Class | ForeignKeyConstraint Members | System.Data Namespace | ForeignKeyConstraint Constructor Overload List