Error Handling Method 4: Day 4 of 23

This article explains error handling using global filters for all controllers and how to display a custom view.

Step 1

Create a MVC project from the "Empty" template. Right-click on "Controllers" and select "Add" >> "Controller...".

Step 2

Select "MVC 5 Controller - Empty" to add an empty controller. Click on the "Add" button.

Step 3

Name the controller "HomeController". The Index() action result method will be added.

Step 4

To add a view, right-click on "Index" and select "Add View...".

Step 5

Name the view and select "Empty (without model)" as the template. Click on the "Add" button.

Step 6

Now we need to create a custom error page so that when an error occurrs, this custom error page is displayed. This error page is common for many kinds of errors generated by any page. So we create it under the shared folder.

Right-click on “Views”, select “Add” >> “New Folder”.

add new folder in View

Step 7

Name the folder "Shared"; this will create a "Shared" folder under the view.

Shared folder in View

Step 8

Right-click on the "Shared" folder and select "Add" >> "View…".

add new view folder in share folder

Step 9

Name the view as "Error" and select "Empty (without model)" as the template.

change view name

Step 10

Design your desired custom error page in Error.cshtml.

design of custom error page

Step 11

Open the web.config file, set customErrors mode=”On” under system.web. If you do not want to display a custom error page then you can set it to “Off”.

custom error mode

Step 12

Let's create a page that we want to display (not an error page). in other words help page. This page we should create under the “Shared” folder.

Right-click on the “Shared” folder, select “Add” >> “View…”.

add view in shared folder

Step 13

Name the view as "Help" and select "Empty (without model)" as the template.

change view folder name as help

Step 14

Design your desired help page in Help.cshtml.

designview of help page

Step 15

Generate an exception inside the index action method.

home controller

Step 16

Right-click on “App_Start”, select “Add” >> “Class…”.

add class in apps folder

Step 17

Select “Class” from the installed template and provide an appropriate name like "ErrorConfig".

add new Debugger Visualizer

Step 18

In the following code snippet you can see the static method that accepts a GlobalFilterCollection. Create an object of HandleErrorAttribute and set the view that you want to display when an exception is thrown. Then add a HandleErrorAttribute object to the GlobalFilterCollection.

error config file

Step 19

Now call this static method inside the Application_Start event of Global.asax.cs, so that it will implement as soon as the application starts.

globle aspx page

Step 20

Now run the project and you will get a NullReferenceException since the session "temp" is not available.

Null Reference Exception

Step 21

Press "F5" and it displays a help page, not an error page.

help page

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