SPField.EnforceUniqueValues property

Gets or sets a Boolean value that specifies whether to enforce uniqueness in column values. The default is false.

Namespace:  Microsoft.SharePoint
Assembly:  Microsoft.SharePoint (in Microsoft.SharePoint.dll)

'Declaration
Public Property EnforceUniqueValues As Boolean
    Get
    Set
'Usage
Dim instance As SPField
Dim value As Boolean

value = instance.EnforceUniqueValues

instance.EnforceUniqueValues = value

public bool EnforceUniqueValues { get; set; }

Type: System.Boolean
Returns true to enforce uniqueness in values that populate a specified column; otherwise false. The default is false.

When you set this property to true, you should also set the Indexed property to true.

The equivalent XML attribute for the Field element in a field definition is AllowDuplicateValues.

SPField class

SPField members

Microsoft.SharePoint namespace

Enforcing Uniqueness in Column Values