Connection String for EntityFramework Core in Azure Web App

Question

I'm having an issue with an Azure SQL DB (SQL PaaS) connection string in my Azure Web App. It is defined in the "Connection Strings" settings of the Application Config. I see the Conn String value (format below) in https://myAppName.scm.azurewebsites.net/Env.cshtml#connectionStrings . My defined Conn String name is "MyApp" and Azure is prefixing it with "SQLAZURECONNSTR_" as you'd expect.

SQLAZURECONNSTR_MyApp = Server=tcp:mysvr.database.windows.net,1433;Initial Catalog=MyApp;Persist Security Info=False;User ID=user@mysvr;Password=passWord;MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;

In Startup.cs, I have this though I'm not certain it is necessary.

        public void ConfigureServices(IServiceCollection services)
        {
[...]
            services.AddDbContext<MyAppContext>(options =>
             options.UseSqlServer(Configuration.GetConnectionString("MyApp")));

And in my database context class, I have the following:

    public partial class MyAppContext : DbContext
    {
[...]
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            if (!optionsBuilder.IsConfigured)
            {
                IConfigurationRoot configuration = new ConfigurationBuilder()
                   .SetBasePath(Directory.GetCurrentDirectory())
                   .AddJsonFile("appsettings.Development.json", optional: true, reloadOnChange: true)
                   .Build();
                var connectionString = configuration.GetConnectionString("MyApp");
                optionsBuilder.UseSqlServer(connectionString);
            }
        }
    }

When accessing the web app executing a method that connects to the database, I'm receiving a null reference to the conn string.

ArgumentNullException: Value cannot be null. (Parameter 'connectionString')
Microsoft.EntityFrameworkCore.Utilities.Check.NotEmpty(string value, string parameterName)
Microsoft.EntityFrameworkCore.SqlServerDbContextOptionsExtensions.UseSqlServer(DbContextOptionsBuilder optionsBuilder, string connectionString, Action<SqlServerDbContextOptionsBuilder> sqlServerOptionsAction)
myapp.Models.MyAppContext.OnConfiguring(DbContextOptionsBuilder optionsBuilder) in MyAppContext.cs

No conn strings are defined in the local .json file, though I'll want to add that back for development purposes at some point.

Answer 1

NEWEST

Code First.

Database Initialization in Entity Framework 6

connectionStr should be like this.

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <connectionStrings>
    <add name="SchoolDBConnectionString" connectionString="tcp:servername.database.windows.net,1433;Initial Catalog=db; Persist Security Info=False; User ID=user;Password=mypassword; MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;" providerName="System.Data.SqlClient"/>
    </connectionStrings>
</configuration>

PRIVIOUS

DB First.

Your project use ef core , so the connectionstrings should be like below.

<connectionStrings>
<add name="SchoolDBEntities" connectionString="metadata=res://*/SchoolDB.csdl|res://*/SchoolDB.ssdl|res://*/SchoolDB.msl;provider=System.Data.SqlClient;provider connection string=&quot;data source=.\sqlexpress;initial catalog=SchoolDB;integrated security=True;multipleactiveresultsets=True;application name=EntityFramework&quot;" providerName="System.Data.EntityClient"/>
</connectionStrings>

For more details, you can refer my answer in the post.

Timeout period elasped prior to obtaining a connection from the pool - Entity Framework

You can also refer to this tutorial, which will help you.

Entity Framework Tutorial