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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

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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