C＃如何在接口中使用泛型约束

Question

Can anyone help me what am i doing wrong with the following c# code? I am basically trying to add the constraint to ICommandHandler.

public interface ICommand<T> where T : BaseDto{ }

public abstract class BaseCommand<T> : ICommand<T> where T : BaseDto { }

public class CreateAlertCommand : BaseCommand<AlertDto>{}   

public interface ICommandHandler<TCommand> where TCommand : ICommand{}

I am getting error when defining ICommandHandler. It says 'Using the generic type ICommand<T> requires 1 type argument'

Answer 1

public interface ICommandHandler<TCommand>
    where TCommand : ICommand
{
}

Should be:

public interface ICommandHandler<TCommand,TDto>
    where TCommand : ICommand<TDto>
    where TDto : BaseDto
{
}