Question

就像this question我在调用具有“params”关键字的方法时遇到问题。我一直得到TargetParameterCountException异常。 “参数计数不匹配”。目标是在没有参数的情况下调用此方法：

IList<T> List(params Expression<Func<T, object>>[] includeProperties);

这是我到目前为止所做的：

        //Get generic type
        var entityType = typeof(Applicant).Assembly.GetType(string.Format("Permet.BackEnd.ETL.Domain.Models.{0}", tableName));
        //create service that will receive the generic type
        var constructedIService = typeof(IService<>).MakeGenericType(entityType);

        //create the argument for the method that we invoke
        var paramsType = typeof(Expression<>).MakeGenericType(typeof(Func<,>).MakeGenericType(entityType, typeof(object))).MakeArrayType();

        //instantiate the service using Unity (todo: fix singleton)
        var serviceInstance = UnitySingleton.Container.Resolve(constructedIService, "");

        //Invoke the service method "List" by passing it no parameters but telling it the signature to use (it has no overloads)
        //I tried without listing the params since it has no overload but same exception
        //I get exception Parameter count mismatch here
        dynamic data = serviceInstance.GetType().GetMethod("List", new Type[] { paramsType }).Invoke(serviceInstance, new object[] { });

请注意，我尝试过传递null并使用重载GetMethod（字符串名称），结果完全相同。

Answer 1

尝试使用单个参数null调用它，因为C＃编译器会将方法签名从method(params object[] parameters)重写为method(object[] parameters)以及对该方法的调用。

dynamic data = serviceInstance.GetType().GetMethod("List", new Type[] { paramsType }).Invoke(serviceInstance, new object[] { null });

使用不带参数的“params”关键字的反射调用方法

1 个答案: