Add-Migration导致InvalidOperationException错误。 正确的命令是什么？

Question

I was doing the tutorial from this website and stuck halfway.

https://docs.microsoft.com/en-us/ef/core/get-started/uwp/getting-started

I was stuck at this line

Add-Migration MyFirstMigration

This are the errors that I get

System.InvalidOperationException: No database provider has been configured for this DbContext. A provider can be configured by overriding the DbContext.OnConfiguring method or by using AddDbContext on the application service provider. If AddDbContext is used, then also ensure that your DbContext type accepts a DbContextOptions object in its constructor and passes it to the base constructor for DbContext.

It seems this error has been going on for some time but so far, Microsoft hasnt respond with a fix.

What should I do?

Answer 1

ApplicationDbContext.cs

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlite("Filename=yorudbname.db");

    }

    //ONLY necessary if you needing to use Fluent API
    protected override void OnModelCreating(ModelBuilder mb)
    {
        base.OnModelCreating(mb);   //required reference comment - Order Matters as well.
                                    //ie has to be at the top.

now you will need to 2 other piece data in your project.json 1) Design 2) Tools listed below.

project.json

    "dependencies": {
    "Microsoft.EntityFrameworkCore.Design": "1.1.1",   <<required
    "Microsoft.EntityFrameworkCore.Sqlite": "1.1.1",
    "Microsoft.NETCore.UniversalWindowsPlatform": "5.3.1",  << must be 5.2.2 or higher
    "Microsoft.Xaml.Behaviors.Uwp.Managed": "2.0.0",
    "MvvmLight": "5.3.0",
    "Newtonsoft.Json": "10.0.2",
    "Unity": "4.0.1"
  },
  "tools": {
    "Microsoft.EntityFrameworkCore.Tools": "1.0.1" << required

don't pay any attention to the versions in this example get the latest version available .

make sure all that is correctly placed and recompile, might even have to close project and reopen, commands should run then.