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UniqueConstraint.Columns Property

Gets the array of columns that this constraint affects.

Namespace:  System.Data
Assembly:  System.Data (in System.Data.dll)

public virtual DataColumn[] Columns { get; }

Property Value

Type: System.Data.DataColumn[]
An array of DataColumn objects.

The following example returns the DataColumn objects that the UniqueConstraint constrains.

Private Sub GetColsFromConstraint()
    Dim dataColumns() As DataColumn

    ' Get a named relation from a DataSet. 
    Dim dataRelation As DataRelation
    dataRelation = DataSet1.Relations("CustomerOrders")

    ' Get the ParentKeyConstraint 
    Dim uniqueConstraint As UniqueConstraint
    uniqueConstraint= dataRelation.ParentKeyConstraint

    ' Get the DataColumn objects being constrained.
    dataColumns = uniqueConstraint.Columns

    ' Print the column name of each column. 
    Dim i As Integer 
    For i = 0 to dataColumns.GetUpperBound(0)
       Console.Write(dataColumns(i).ColumnName)
    Next i
 End Sub

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0

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