Queryable.Union<TSource> Method (IQueryable<TSource>, IEnumerable<TSource>)
Produces the set union of two sequences by using the default equality comparer.
Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)
public static IQueryable<TSource> Union<TSource>( this IQueryable<TSource> source1, IEnumerable<TSource> source2 )
Type Parameters
- TSource
The type of the elements of the input sequences.
Parameters
- source1
- Type: System.Linq.IQueryable<TSource>
A sequence whose distinct elements form the first set for the union operation.
- source2
- Type: System.Collections.Generic.IEnumerable<TSource>
A sequence whose distinct elements form the second set for the union operation.
Return Value
Type: System.Linq.IQueryable<TSource>An IQueryable<T> that contains the elements from both input sequences, excluding duplicates.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable<TSource>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).| Exception | Condition |
|---|---|
| ArgumentNullException | source1 or source2 is null. |
The Union<TSource>(IQueryable<TSource>, IEnumerable<TSource>) method generates a MethodCallExpression that represents calling Union<TSource>(IQueryable<TSource>, IEnumerable<TSource>) itself as a constructed generic method. It then passes the MethodCallExpression to the CreateQuery<TElement>(Expression) method of the IQueryProvider represented by the Provider property of the source1 parameter.
The query behavior that occurs as a result of executing an expression tree that represents calling Union<TSource>(IQueryable<TSource>, IEnumerable<TSource>) depends on the implementation of the type of the source1 parameter. The expected behavior is that the set union of the elements in source1 and source2 is returned.
The following code example demonstrates how to use Union<TSource>(IQueryable<TSource>, IEnumerable<TSource>) to obtain the set union of two sequences.
int[] ints1 = { 5, 3, 9, 7, 5, 9, 3, 7 };
int[] ints2 = { 8, 3, 6, 4, 4, 9, 1, 0 };
// Get the set union of the items in the two arrays.
IEnumerable<int> union = ints1.AsQueryable().Union(ints2);
foreach (int num in union)
Console.Write("{0} ", num);
/*
This code produces the following output:
5 3 9 7 8 6 4 1 0
*/
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.
