ConstraintCollection.Add Method (String, DataColumn, Boolean)


Constructs a new UniqueConstraint with the specified name, DataColumn, and value that indicates whether the column is a primary key, and adds it to the collection.

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

public Constraint Add(
	string name,
	DataColumn column,
	bool primaryKey


Type: System.String

The name of the UniqueConstraint.

Type: System.Data.DataColumn

The DataColumn to which the constraint applies.

Type: System.Boolean

Specifies whether the column should be the primary key. If true, the column will be a primary key column.

Return Value

Type: System.Data.Constraint

A new UniqueConstraint.

Exception Condition

The constraint already belongs to this collection.


The constraint belongs to another collection.


The collection already has a constraint with the specified name. (The comparison is not case-sensitive.)

The CollectionChanged event occurs if the constraint is added successfully.

The following example uses the Add method to create and add a new UniqueConstraint to a ConstraintCollection.

private void AddUniqueConstraint(DataTable table){
   table.Constraints.Add("idConstraint", table.Columns["id"], true);

.NET Framework
Available since 1.1
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