AcceptRejectRule AcceptRejectRule AcceptRejectRule AcceptRejectRule Enum

Definizione

Determina l'azione eseguita quando viene chiamato il metodo AcceptChanges() o il metodo RejectChanges() su un oggetto DataTable con un vincolo ForeignKeyConstraint.Determines the action that occurs when the AcceptChanges() or RejectChanges() method is invoked on a DataTable with a ForeignKeyConstraint.

public enum class AcceptRejectRule
public enum AcceptRejectRule
type AcceptRejectRule = 
Public Enum AcceptRejectRule
Ereditarietà
AcceptRejectRuleAcceptRejectRuleAcceptRejectRuleAcceptRejectRule

Campi

Cascade Cascade Cascade Cascade 1

Le modifiche vengono estese alla relazione.Changes are cascaded across the relationship.

None None None None 0

Non viene eseguita alcuna azione (impostazione predefinita).No action occurs (default).

Esempi

Nell'esempio seguente viene creato ForeignKeyConstraintun oggetto, vengono impostate diverse proprietà, AcceptRejectRuleincluso, e viene aggiunto a un DataTable oggetto ConstraintCollection.The following example creates a ForeignKeyConstraint, sets various of its properties, including the AcceptRejectRule, and adds it to a DataTable object's ConstraintCollection.

private void CreateConstraint(DataSet dataSet, 
    string table1, string table2,string column1, string column2)
{
   // Declare parent column and child column variables.
   DataColumn parentColumn;
   DataColumn childColumn;
   ForeignKeyConstraint foreignKeyConstraint;

   // Set parent and child column variables.
   parentColumn = dataSet.Tables[table1].Columns[column1];
   childColumn = dataSet.Tables[table2].Columns[column2];
   foreignKeyConstraint = new ForeignKeyConstraint
      ("SupplierForeignKeyConstraint",  parentColumn, childColumn);

   // Set null values when a value is deleted.
   foreignKeyConstraint.DeleteRule = Rule.SetNull;
   foreignKeyConstraint.UpdateRule = Rule.Cascade;
   foreignKeyConstraint.AcceptRejectRule = AcceptRejectRule.None;

   // Add the constraint, and set EnforceConstraints to true.
   dataSet.Tables[table1].Constraints.Add(foreignKeyConstraint);
   dataSet.EnforceConstraints = true;
}
Private Sub CreateConstraint(dataSet As DataSet, _
   table1 As String, table2 As String, _
   column1 As String, column2 As String)

   ' Declare parent column and child column variables.
   Dim parentColumn As DataColumn
   Dim childColumn As DataColumn
   Dim foreignKeyConstraint As ForeignKeyConstraint

   ' Set parent and child column variables.
   parentColumn = dataSet.Tables(table1).Columns(column1)
   childColumn = dataSet.Tables(table2).Columns(column2)
   foreignKeyConstraint = New ForeignKeyConstraint _
      ("SupplierForeignKeyConstraint", parentColumn, childColumn)

   ' Set null values when a value is deleted.
   foreignKeyConstraint.DeleteRule = Rule.SetNull
   foreignKeyConstraint.UpdateRule = Rule.Cascade
   foreignKeyConstraint.AcceptRejectRule = AcceptRejectRule.None

   ' Add the constraint, and set EnforceConstraints to true.
   dataSet.Tables(table1).Constraints.Add(foreignKeyConstraint)
   dataSet.EnforceConstraints = True
End Sub

Commenti

Le modifiche a DataTable un oggetto non sono finali fino a AcceptChanges quando non si chiama il metodo.Changes to a DataTable are not final until you call the AcceptChanges method. Quando si chiama RejectChanges AcceptRejectRule o in una riga della tabella padre, il valore determina se le modifiche vengono propagate alle righe corrispondenti della tabella figlio. AcceptChangesWhen either AcceptChanges or RejectChanges is called on a row in the parent table, the AcceptRejectRule value determines whether or not changes are propagated to corresponding rows in the child table.

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