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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: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

XNA Framework

Supported in: 3.0, 2.0, 1.0
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