This topic has not yet been rated - Rate this topic

DataColumn.Unique Property

.NET Framework 3.5

Other Versions

Gets or sets a value that indicates whether the values in each row of the column must be unique.

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

Syntax

C++

JScript

public bool Unique { get; set; }

Property Value

Type: System.Boolean
true if the value must be unique; otherwise, false. The default is false.

Exceptions

Exception	Condition
ArgumentException	The column is a calculated column.

Remarks

As soon as this property is changed from false to true, a unique constraint will be created on this column to make sure that values are unique.

Examples

The following example creates new DataColumn, sets its properties, and adds it to a table's columns collection.

private void AddColumn(DataTable table)
{
    // Add a DataColumn to the collection and set its properties. 
    // The constructor sets the ColumnName of the column.
    DataColumn column = new DataColumn("Total");
    column.DataType = System.Type.GetType("System.Decimal");
    column.ReadOnly = true;
    column.Expression = "UnitPrice * Quantity";
    column.Unique = false;
}

Platforms

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.

Version Information