WPF Core - Connection Strings inside App.config Not Working

Question

Upon facing the said issue even followed the simple walkthrough at Connection Strings - EF Core but found out that while hardcoding the connectionstring as:

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
    optionsBuilder.UseSqlServer(@"Server=(localdb)\mssqllocaldb;Database=Blogging;Trusted_Connection=True;");
}

leads to success, using the recommended approach of inserting an App.config file like:

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <connectionStrings>
    <add name="BloggingDatabase"
         connectionString="Server=(localdb)\mssqllocaldb;Database=Blogging;Trusted_Connection=True;" providerName="System.Data.SqlClient" />
  </connectionStrings>
</configuration>

and updating the main code to:

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
    optionsBuilder.UseSqlServer(ConfigurationManager.ConnectionStrings["BloggingDatabase"].ConnectionString);
}

is not successful, and following error being faced while carrying out migration:

System.NullReferenceException: Object reference not set to an instance of an object.
   at Intro.BloggingContext.OnConfiguring(DbContextOptionsBuilder optionsBuilder) in C:\<...FileLocation...>\AppDbContext.cs:line 14
   at Microsoft.EntityFrameworkCore.DbContext.get_InternalServiceProvider()
   at Microsoft.EntityFrameworkCore.DbContext.Microsoft.EntityFrameworkCore.Infrastructure.IInfrastructure<System.IServiceProvider>.get_Instance()
   at Microsoft.EntityFrameworkCore.Infrastructure.Internal.InfrastructureExtensions.GetService[TService](IInfrastructure`1 accessor)
   at Microsoft.EntityFrameworkCore.Infrastructure.AccessorExtensions.GetService[TService](IInfrastructure`1 accessor)
   at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.CreateContext(Func`1 factory)
   at Microsoft.EntityFrameworkCore.Design.Internal.DbContextOperations.CreateContext(String contextType)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.AddMigration(String name, String outputDir, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigration.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
Object reference not set to an instance of an object.

What could be the reason behind the same?

Thanks in advance for your reviewing and replying.

Did you check this properties `ConfigurationManager.ConnectionStrings["BloggingDatabase"].ConnectionString`? — Pavel Anikhouski, Mar 28 '20 at 15:18
Does this answer your question? [Is ConfigurationManager.AppSettings available in .NET Core 2.0?](https://stackoverflow.com/questions/47591910/is-configurationmanager-appsettings-available-in-net-core-2-0) — Pavel Anikhouski, Mar 28 '20 at 15:19
If you are referring to use of the namespace **System.Configuration** I have done the same plus the said property being completely being referred to as the following does not resolve the said problem: optionsBuilder.UseSqlServer(System.Configuration.ConfigurationManager.ConnectionStrings["BloggingDatabase"].ConnectionString); — Faraz Ahmed Qureshi, Mar 28 '20 at 16:31
**Strange!!!** Upon using the index technique i.e. like: **optionsBuilder.UseSqlServer(System.Configuration.ConfigurationManager.ConnectionStrings[0].ConnectionString);** is successful! — Faraz Ahmed Qureshi, Mar 28 '20 at 17:06

score 0 · Answer 1 · answered Apr 17 '20 at 17:47

0

Finally found the only satisfying answer to a mirror question here.

App.Config is not a correct choice for Connection Strings for WPF Core. It's rather an appsettings.json file successful enough in this regard.

answered Apr 17 '20 at 17:47

Faraz Ahmed Qureshi

88
1
1
11

score 0 · Answer 2 · answered Dec 15 '20 at 00:58

0

Strange!!! Upon using the index technique i.e. like: optionsBuilder.UseSqlServer(System.Configuration.ConfigurationManager.ConnectionStrings[0].ConnectionString); is successful! – Faraz Ahmed Qureshi Mar 28 at 17:06

Indeed this works

answered Dec 15 '20 at 00:58

Somang

33
6

WPF Core - Connection Strings inside App.config Not Working

2 Answers2