Since exception handling is the part of the request processing, to handle exceptions during action method execution, we can instruct the controller to execute common exception logic. Since Controller Name and Action Name is used in the URL for MVC request processing, we can configure controller to make use of some common logic for execution, which will be used to handle the request.
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Implementation of Exception Handling using OnException method overriding of the Controller base classĬontroller is the most important component of MVC and plays a major role in request processing.
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In the traditional programming this approach looks good with the limitation that the exception code is specific to the action method, so we need to write it in each action method separately. Once the Back button is clicked, the same create view will be displayed. On clicking Submit, the control will be navigated to the error page: Enter data into textboxes with the duplicate value for EmpNo. To test this, run the application and visit the Create view using the following URL:
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Step 6: Open Error.Cshtml and add the following code in error occurred while processing your above CSHTML uses the HandleErrorInfo model object to display error messages in the View.
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The action method is trying to save EmployeeInfo object using EF, so the type of exception that occurs in the code is of the type DbUpdateException in case of primary key duplicity or any other database update issues.
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(In the Step 1 we already discussed the Error View and its HandleError Model class). This accepts the View Name as first parameter and the Model as second. In the above code, we are using one of the View() overloads. Return View("Error",new HandleErrorInfo(ex,"EmployeeInfo","Create")) Step 5: In the EmployeeInfoController, change the implementation of the Create action method as shown here: Using an easy exception handling mechanism using traditional coding i.e. Since MVC is a pattern for Web development, as a developer it is our responsibility to think and use the most appropriate options from the above. Handling Exceptions at global level using FilterConfig Class. Use and override OnException method of the Controller base class.ģ. Use try-catch local to each action method.Ģ. In ASP.NET MVC, in controller class exceptions can be handled with the following ways:ġ. Thankfully we have try-catch block to handle exceptions. Implementing Exceptions in ASP.NET MVC appsĪs a developer we need to understand and locate the code which has a chance of triggering an exception. Public ActionResult Create(EmployeeInfo Emp)įrom the above code, scaffold the Index and Create Views. Public class EmployeeInfoController : Controller Now implement action methods, which calls the EF we just created: Step 4: In the controllers, add a new MVC controller of the name EmployeeInfoController. After completion of the wizard, the mapping will be as seen here: In the wizard, select Application.mdf and EmployeeInfo Table. Step 3: In the Models folder, right-click and add a new ADO.NET Entity Data Model of the name ApplicationEDMX. Step 2: In the App_Data folder add a new Sql Server Database of the name Application and create an EmployeeInfo table in it: (We will anyways see it in the following steps.) We can make use of these properties to implement logic at view level.
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The class also provides properties for Exception, Controller and Action Name. This can be used to pass Exception type, controller and action names to the Error View to display error details. Public HandleErrorInfo(Exception exception, string controllerName, string actionName) This class contains parameterized constructor as shown here: This is the error view with HandleErrorInfo as model class. The Views folder has a Shared subfolder with Error.cshtml in it. This creates a MVC project with folders for Models, View, App_Data and Controllers etc.
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Step 1: Open Visual Studio 2013, (the implementation uses VS 2013 Ultimate with Update 4 although you can very well use the Free Visual Studio Community Edition) and create a new MVC 5 application. In the implementation below, I will demonstrate various ways of handling exceptions. However what if our code encounters an exception and we need to redirect to the Error View? This may be needed with various action methods across various controllers. We are habitual to make use of try-catch-finally block to handle exceptions, but in case of ASP.NET MVC, while working with action methods we generally write code to redirect to the Index View using RedirectToAction(“Index”). HandlerError is used to handle exceptions while executing action methods. request Logging, authorization, HandlerError etc. MVC already provides Action Filter feature for implementing add-on application logic e.g. While developing Line-of-Business (LOB) applications using ASP.NET MVC, we come across various requirements varying from doing Model Validations to handling Exceptions.