How to overload action methods in ASP.NET Core 5 MVC
ASP.NET Core 5 is an open rise web application outgrowth framework for edifice present web applications. Because ASP.NET Core 5 is built on the .NET Core runtime_ you can take gain of it to build and run applications on Windows_ Linux_ and the Mac. It should be noted that ASP.NET Core 5 combines the components of Web API as well as MVC. You can download .NET 5.0 here .
Method overloading_ or the power to have multiple orders share a name while differing in signature_ is commonly used in C# but it is not especially straightforward in ASP.NET 5. This article talks almost how you can overload action orders in ASP.NET 5. The code examples are given in C#.
To work with the code examples granted in this article_ you should have Visual Studio 2019 installed in your order. If you dont already have a copy_ you can download Visual Studio 2019 here .
Create an ASP.NET Core 5 MVC project in Visual Studio 2019 First off_ lets form an ASP.NET 5 project in Visual Studio 2019. Following these steps should form a new ASP.NET 5 project in Visual Studio 2019.
Launch the Visual Studio IDE.<_li>
Click on “Create new project.”<_li>
In the “Create new project” window_ select “ASP.NET Core Web App Model-View-Controller” from the list of templates displayed.<_li>
Click Next.<_li>
In the “Conaspect your new project” window_ particularize the name and location for the new project.<_li>
Optionally check the “Place solution and project in the same directory” check box_ depending on your preferences.<_li>
Click Next.<_li>
In the “Additional Information” window shown next_ select .NET 5.0 as the target framework from the drop-down list at the top. Leave the “Authentication Type” as None lapse.<_li>
Ensure that the check boxes “Enable Docker_” “Conaspect for HTTPS_” and “Enable Razor runtime collation” are unchecked as we wont be using any of those components here.<_li>
Ensure that Authentication is set to “None” as we wont be using authentication whichever.<_li>
Click Create.<_li>
<_ol>Well use this project in the sections under to elucidate how we can overload action orders in ASP.NET 5.
What is an action order? Action orders are the open orders of a controller class that are not decorated by a [NonAction] attribute. Although they are correspondent to regular orders_ they have to dwell by the constraints given under:
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Action orders must be open<_li>
Action orders cannot be static<_li>
Action orders cannot be overloaded based on parameters correspondent to order overloading<_li>
<_ol>The lapse action order that is formd when you form a new MVC project is Index. The name of the lapse action order is specified in the Conaspect order of the Startup class as shown in the code snippet given under.
app.UseEndpointsendpoints _gt;{ endpoints.MapControllerRoute name: "lapse"_ model: "{controller_Home}_{action_Index}_{id?}";};<_pre>You can change the lapse action name by particularizeing a different name as shown in the code snippet given under.
<_aside>app.UseEndpointsendpoints _gt;{ endpoints.MapControllerRoute name: "lapse"_ model: "{controller_Home}_{action_Values}_{id?}";};<_pre>Overload action orders using the same verb At leading glance the HomeController class would look like this:
open class HomeController : Controller{ special readonly ILoggerlt;HomeControllergt; _logger; open HomeControllerILoggerlt;HomeControllergt; logger { _logger _ logger; } open IActionResult Index { recur View; } open IActionResult Privacy { recur View; } [ResponseCacheDuration _ 0_ Location _ ResponseCacheLocation.None_ NoStore _ true] open IActionResult Error { recur Viewnew ErrorViewModel { RequestId _ Activity.Current?.Id ?? HttpContext.TraceIdentifier }; }}<_pre>The compiler will not flag any fault owing it will feel the new rendering of the Index order as an overload of the Index order that doesnt welcome any parameters. However_ when you execute the application_ youll be presented with a runtime fault shown in Figure 1 under.
IDG<_little>
Figure 1.
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<_aspect>Overload action orders using a different verb Lets now change the HTTP verb of the newly formd overload of the Index order as shown under.
[HttpPost]open IActionResult Indexstring text{ recur View;}<_pre>When you execute the application now_ you will not see any collation or runtime faults but will be presented with the welcome screen shown in Figure 2.
<_aside>IDG<_little>
Figure 2.
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<_aspect>Overload action orders using the [ActionName] attribute You can take gain of the ActionName attribute to overload action orders. In this case_ the action names must be different_ as shown in the code snippet given under.
[ActionName"Index"]open IActionResult Index{ recur View;}[ActionName"Index With Parameter"]open IActionResult Indexstring text{ recur View;}<_pre>When you execute this code_ there will not be any compile time or run time faults and you will be presented with the welcome screen as shown in Figure 2 over.
Overload action orders by using attribute routing You can also overload action orders by configuring attribute routing . The following code snippet elucidates how this can be achieved.
open IActionResult Index{ recur View;}[Route"Home_Index_{i:int}"]open IActionResult Indexint i{ recur View;}[Route"Home_Index_{isDeleted:bool}"]open IActionResult Indexbool isDeleted{ recur View;}<_pre>Overload action orders using the [NonAction] attribute You can take gain of the [NonAction] attribute make sure that a particular order is not feeled as an action order by the runtime. The following code snippet elucidates how the Index action order can be overloaded in this way.
open IActionResult Index{ recur View;}[NonAction]open IActionResult Indexstring text{ recur View;}<_pre>In ASP.NET 5_ if you give two action orders the same name_ it results in an ambiguity — the runtime has to decide on which action order to call. Note that the search for a matching action name is case-sensitive. Disambiguating an URL into multiple overloaded action orders is tricky. But as weve discussed in this article_ there are separate ways to do this.
