DataRelation.ParentKeyConstraint 属性

定义

命名空间:

System.Data

程序集:

System.Data.Common.dll

Source:

DataRelation.cs

获取 UniqueConstraint，它确保 DataRelation 的父列中的值是唯一的。

public:
 virtual property System::Data::UniqueConstraint ^ ParentKeyConstraint { System::Data::UniqueConstraint ^ get(); };

public virtual System.Data.UniqueConstraint? ParentKeyConstraint { get; }

member this.ParentKeyConstraint : System.Data.UniqueConstraint

Public Overridable ReadOnly Property ParentKeyConstraint As UniqueConstraint

属性值

UniqueConstraint

一个 UniqueConstraint，它确保父列中的值是唯一的。

示例

以下示例获取 ParentKeyConstraintDataRelation 对象的 。

Private Sub GetParentKeyConstraint()
    ' Get a DataRelation from a DataSet.
    Dim relation As DataRelation = _
        DataSet1.Relations("CustomerOrders")

    ' Get the relations parent key constraint.
    Dim constraint As UniqueConstraint = _
        relation.ParentKeyConstraint

    ' Get the constraint's DataColumns
    Dim constraintColumns() As DataColumn
    constraintColumns = constraint.Columns

    ' Print the column names.
    Dim i As Integer
    For i = 0 to constraintColumns.GetUpperBound(0)
       Console.WriteLine(constraintColumns(i).ColumnName.ToString())
    Next i
End Sub

另请参阅

• ChildKeyConstraint
• UniqueConstraint