Conversions in LINQ
The operators change the type of input objects and are used in a diverse range of applications.
Operator | Description | C# Query Expression Syntax | VB Query Expression Syntax |
---|---|---|---|
AsEnumerable | Returns the input typed as IEnumerable<T> | Not Applicable | Not Applicable |
AsQueryable | A (generic) IEnumerable is converted to a (generic) IQueryable | Not Applicable | Not Applicable |
Cast | Performs casting of elements of a collection to a specified type | Use an explicitly typed range variable. Eg:from string str in words | From … As … |
OfType | Filters values on basis of their , depending on their capability to be cast to a particular type | Not Applicable | Not Applicable |
ToArray | Forces query execution and does conversion of a collection to an array | Not Applicable | Not Applicable |
ToDictionary | On basis of a key selector function set elements into a Dictionary<TKey, TValue> and forces execution of a LINQ query | Not Applicable | Not Applicable |
ToList | Forces execution of a query by converting a collection to a List<T> | Not Applicable | Not Applicable |
ToLookup | Forces execution of a query and put elements into a Lookup<TKey, TElement> on basis of a key selector function | Not Applicable | Not Applicable |
Example of Cast - Query Expression
C#
using System; using System.Linq; namespace Operators { class Cast { static void Main(string[] args) { Plant[] plants = new Plant[] {new CarnivorousPlant { Name = "Venus Fly Trap", TrapType = "Snap Trap" }, new CarnivorousPlant { Name = "Pitcher Plant", TrapType = "Pitfall Trap" }, new CarnivorousPlant { Name = "Sundew", TrapType = "Flypaper Trap" }, new CarnivorousPlant { Name = "Waterwheel Plant", TrapType = "Snap Trap" }}; var query = from CarnivorousPlant cPlant in plants where cPlant.TrapType == "Snap Trap" select cPlant; foreach (var e in query) { Console.WriteLine("Name = {0} , Trap Type = {1}", e.Name, e.TrapType); } Console.WriteLine("\nPress any key to continue."); Console.ReadKey(); } } class Plant { public string Name { get; set; } } class CarnivorousPlant : Plant { public string TrapType { get; set; } } }
VB
Module Module1 Sub Main() Dim plants() As Plant = {New CarnivorousPlant With {.Name = "Venus Fly Trap", .TrapType = "Snap Trap"}, New CarnivorousPlant With {.Name = "Pitcher Plant", .TrapType = "Pitfall Trap"}, New CarnivorousPlant With {.Name = "Sundew", .TrapType = "Flypaper Trap"}, New CarnivorousPlant With {.Name = "Waterwheel Plant", .TrapType = "Snap Trap"}} Dim list = From cPlant As CarnivorousPlant In plants Where cPlant.TrapType = "Snap Trap" Select cPlant For Each e In list Console.WriteLine("Name = {0} , Trap Type = {1}", e.Name, e.TrapType) Next Console.WriteLine(vbLf & "Press any key to continue.") Console.ReadKey() End Sub Class Plant Public Property Name As String End Class Class CarnivorousPlant Inherits Plant Public Property TrapType As String End Class End Module
When the above code in C# or VB is compiled and executed, it produces the following result −
Name = Venus Fly Trap, TrapType = Snap Trap Name = Waterwheel Plant, TrapType = Snap Trap Press any key to continue.
linq_query_operators.htm
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