必须是具有公共无参数构造函数c＃的非抽象类型

Question

I'm trying to do something new and got this error, I have an interface in c#

public interface IRepository<TSource>: IDisposable where TSource: class
{
    TSource GetById(long id);

    List<TSource> GetAll();

    bool InsertOrUpdate(TSource source);

    bool Delete(long id);

    VM.RetornoGenerico<TSource> Upload(long id);
}

The problem is when I pass TSource to my RetornoGenerico Class

public class RetornoGenerico<T> where T : new()
{
    public T Result { get; set; }
    public bool Success { get; set; }
    public string ErrorMsg { get; set; }
    public string IdError { get; set; }

    public RetornoGenerico()
    {
        Result: new T();
        Success = false;

    }

    public static RetornoGenerico<T> CloneError<TU>(RetornoGenerico<TU> resposta) where TU : new()
    {
        var retorno = new RetornoGenerico<T>()
        {
            Success = resposta.Success,
            Result = new T(),
            ErrorMsg = resposta.ErrorMsg,
            IdError = resposta.IdError

        };
        return retorno;
    }
}

I get the following error:

Must be a non abstract type with public parameterless constructor

Can someone help me find what is wrong with my code?

Answer 1

由于您的类具有where T : new() ，并且您正在将TSource传递给该类，因此TSource必须具有相同的约束。

public interface IRepository<TSource>: IDisposable where TSource: class, new()