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Build a Simple CRUD App with Angular 8 and ASP.NET Core 2.2 - part 1 - back-end

Martin Soderlund Ek on September 18, 2019

Part 1 - back-end with ASP.NET Core 2.2 and Entity Framework Core Let’s take a look at how to build a CRUD web app using ASP.NET Core 2....

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Matt Ingham • Jun 27 '20

Hi Martin,

This was such a useful tutorial, thank you! I knew a little Angular and a little ASP.NET and this was perfect for filling the gaps and getting an application up and running.

My only question is why do you only use the DataRepository for the POST/PUT methods and stick with the db context for the GET methods?
Thanks Matt

Cameron Thompson • Jan 9 '20

Hello Martin,

This tutorial is great!

I am, however, getting stuck on the adding the migration section of this tutorial. When I type "Add-Migration Initial" the build starts then fails imminently.

Any ideas on what is causing this?

Thanks again!
Cameron

Martin Soderlund Ek • Jan 9 '20

Hi and thanks!

Does the solution build? Do you get any build errors?

I tried reproducing your error and could reproduce it when building an old version of this app (with url slugs actually) and got the same migration error. I also got build errors related to TypeScript and IteratorResult.

Then I used VS Code to run ng build in the ClientApp folder and got the following error:

ERROR in src/app/blog-post-add-edit/blog-post-add-edit.component.ts:8:27 - error TS2307: Cannot find module 'path'.

8 import { delimiter } from 'path';

I simply commented out this section in blog-post-add-edit.component.ts and ran ng build again and then building worked.

I finally ran ng serve (which builds and runs the ClientApp application) and then everything worked fine.

Cameron Thompson • Jan 9 '20 • Edited

So after some investigation, I changed line 35 of Startup.cs from "options.UseSqlServer(Configuration.GetConnectionString("BlogPostsContext")));" to "options.UseInMemoryDatabase(Configuration.GetConnectionString("BlogPostsContext")));" This allowed me to skip the section of doing "Add-Migrations Initial"

Martin Soderlund Ek • Jan 14 '20

Thanks for sharing!

Installing these packages via Nuget might solve it too:

Microsoft.EntityFrameworkCore
Microsoft.EntityFrameworkCore.SqlServer

caseygore • Apr 6 '20

I followed the tutorial but when I get to doing a post in post man. I get a "Could not get any response" error. Could you elaborate on how to find your exact url and in my post man I have 9 headers and in your example you have 10.

gavin-campbell-g2g3 • Dec 18 '19

Hi Martin,

Thanks for the tutorial.

I encountered an exception though when I tried to run it:
"The CORS protocol does not allow specifying a wildcard (any) origin and credentials at the same time. Configure the policy by listing individual origins if credentials needs to be supported"

This was caused by setting both "AllowAnyOrigin()" and "AllowCredentials()" when setting up the CORS policy. However, when I remove "AllowCredentials()" and run it, it says the page cannot be found.

Any suggestions on how to overcome this? Has this requirement come into play since you wrote this tutorial, if not how did it work for you?

Any help would be greatly appreciated.

Thanks,
Gavin

bogdanhatis • Dec 31 '19

Hi Gavin,

Yes, you need to remove the AllowCredentials() to run the solution. After that build the solution and the first page will be Not found and you need to put /api/blogposts into the url for calling the get all method.

Best regards,
Bogdan

gavin-campbell-g2g3 • Jan 7 '20 • Edited

Hi Bogdan,

Thanks for the help. I had realised my error but hadn't had a chance to come back and update my comment.

Thanks again for your help!

Gavin

Martin Soderlund Ek • Jan 3 '20

Thanks for clarifying that, Bogdan!

Denise R James • Mar 13 '20

Martin,

If this is not the best tutorial on how get a back end for a blog, I missed it! Thanks for allowing me to have a backend in less than an hour. Now to the front end!