无法在EF Core 6上创建迁移

Question

我在运行dotnet ef migrations add Initial时遇到了这个问题，我不知道是什么原因造成的。问题是我得到了以下错误：

无法创建"ApplicationDbContext"类型的对象。有关设计时支持的不同模式，请参阅https://go.microsoft.com/fwlink/?linkid=851728

我一直在反复检查代码，但找不到问题。

这是我的Program.cs代码：

using Microsoft.EntityFrameworkCore;
using TrainningManagerService.Context;
var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
var app = builder.Build();
// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
app.UseSwagger();
app.UseSwaggerUI();
}
var connectionString = builder.Configuration.GetConnectionString("DefaultConnection");
builder.Services.AddDbContext<ApplicationDbContext>(options =>
{
options.UseMySql(connectionString, ServerVersion.AutoDetect(connectionString));
});
app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();
app.Run();

这是我的ApplicationDbContext:

using Microsoft.EntityFrameworkCore;
using TrainningManagerService.Entities.Database;
namespace TrainningManagerService.Context
{
public class ApplicationDbContext : DbContext
{
public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options) :
base(options)
{
}
public DbSet<Video> Videos { get; set; }
public DbSet<Plan> Plans { get; set; }
}
}

我一直在互联网上搜索，但在任何地方都找不到解决方案，这真的很困扰我，因为我刚刚创建了一个新的解决方案，但我无法创建一个迁移。

Answer 1

这是由Program.cs.中的订单引起的

我不得不向上移动这个部分：

var connectionString = builder.Configuration.GetConnectionString("DefaultConnection");
builder.Services.AddDbContext<ApplicationDbContext>(options =>
{
options.UseMySql(connectionString, ServerVersion.AutoDetect(connectionString));
});

所以它变成了：

var builder = WebApplication.CreateBuilder(args);
// Add services to the container.
builder.Services.AddControllers();
// Learn more about configuring Swagger/OpenAPI at https://aka.ms/aspnetcore/swashbuckle
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
var connectionString = builder.Configuration.GetConnectionString("DefaultConnection");
builder.Services.AddDbContext<ApplicationDbContext>(options =>
{
options.UseMySql(connectionString, ServerVersion.AutoDetect(connectionString));
});
var app = builder.Build();

否则，在应用数据库之前，构建器已经完成