C# - 如何使用类的类型传递泛型类型"this"

Question

我有一个具有GetQueryable方法的User类。另一个方法Select()调用GetQueryable()。我想使用Select方法而不将类型User传递给Select方法，因为我在这个中有它，但我不能使用它。

Type type = this.GetType();

? ?

var x = this.GetQueryable< ?? >().ToList();

class Program
{
    static void Main(string[] args)
    {
        var acc = new User();
        acc.Select();
    }
}
public partial class User
{
    public DB_Test001Entities context;
    public User()
    {
        context = new DB_Test001Entities();
    }
    public void Select()
    {  
        Type type = this.GetType();
        var x = this.GetQueryable< **???** >().ToList();
    }
    public IQueryable<TEntity> GetQueryable<TEntity>(List<string> includes = null) where TEntity : class
    {
        IQueryable<TEntity> items = context.Set<TEntity>();
        if (includes != null && includes.Any())
            includes.Where(i => i != null).ToList().ForEach(i => { items = items.Include(i); });
        return items;
    }
}

Answer 1

您可以使用反射来实现。下面的示例工作得很顺利。在程序中，您可以使用Clerk或Manager，只是从User派生的任何实例调用Select。你可以用这个改进你的程序。

    class Clerk : User { }
    class Manager : User { }
    internal class User
    {
        public User() { }
        public string Name { get; set; }
        public void Select()
        {
            var list = new List<string>() {"Jack", "Martin"};
            Type thisType = GetType();
            MethodInfo method = thisType.GetMethod("GetQueryable").MakeGenericMethod(thisType);
            method.Invoke(this, new object[] {list});
        }
        public IQueryable<TEntity> GetQueryable<TEntity>(List<string> includes = null) where TEntity : User, new()
        {
            if(includes != null)
            {
                Console.WriteLine(typeof(TEntity));
                var entity = new List<TEntity>(includes.Count);
                entity.AddRange(includes.Select(item => new TEntity {Name = item}));
                return entity.AsQueryable();
            }
            return null;
        }
    }
    class Program
    {
        static void Main()
        {
            User usr = new Manager();
            usr.Select();
        }
    }