如何正确实例化具有构造函数的Context

Question

我有一个问题。我有一个类如下：我无法将数据保存到我的数据库。

public class SomeClassContext : DbContext
{ 
    private IConfigurationRoot _configurationRoot;

    public SomeClassContext(DbContextOptions<SomeClassContext> contextOptions, IConfigurationRoot configurationRoot)
    {
        this._configurationRoot = configurationRoot;
    }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        base.OnConfiguring(optionsBuilder);
        optionsBuilder.UseSqlServer(_configurationRoot["Data:ConnectionString"]);
    }

我的appsettings.json

 {
   "Data": {
      "ConnectionString": "Data Source=MyDataSource;Initial Catalog=MyCatalog",
 }

当我尝试实例化SomeClassContext并为构造函数提供参数时，我得到空值

public class MyClass
{
    private SomeClassContext context;
    private string _categoryName;
    private Func<string, LogLevel, bool> _filter;

    public MyClass(string categoryName, Func<string, LogLevel, bool> filter)
    {
        _categoryName = categoryName;
        _filter = filter;
        context = new SomeClassContext(//parameters here are required. What should be my parameters here that will not result to null)
    }

    public void SomeMethod()
    {
        var obj = new MyEntity()
        {
           //assume I have initialize object here
        };
        try
        {
            context.MyEntity.Add(obj);
            context.SaveChanges();
        }
        catch(Exception e)
        {
            //debugger throws here
            //cannot save to DB
        }
    }
}