將函數作爲參數傳遞給動作

Question

我試圖將一個方法作爲一個動作傳遞，但似乎該演員並不是每個人都說的。

這是我正在做它：

public class RequestHandler<T> where T : struct 
{ 
    public enum EmployeeRequests { BasicDetails, DependentsAndEmergencyContacts , MedicalHistory } 

    protected Dictionary<T, Action> handlers = new Dictionary<T, Action>(); 

    protected EmployeeManagement empMgmnt = new EmployeeManagement(); 

    public void InitializeHandler(int employeeID) 
    { 

     this.AddHandler(EmployeeRequests.BasicDetails,() => empMgmnt.GetEmployeeBasicDetails(0)); 
    } 

    public void AddHandler(T caseValue, Action action) 
    { 
     handlers.Add(caseValue, action); 
    } 

    public void RemoveHandler(T caseValue) 
    { 
     handlers.Remove(caseValue); 
    } 

    public void ExecuteHandler(T actualValue) 
    { 
     ExecuteHandler(actualValue, Enumerable.Empty<T>()); 
    } 

    public void ExecuteHandler(T actualValue, IEnumerable<T> ensureExistence) 
    { 
     foreach(var val in ensureExistence) 
      if (!handlers.ContainsKey(val)) 
       throw new InvalidOperationException("The case " + val.ToString() + " is not handled."); 
     handlers[actualValue](); 
    } 
} 

這是我的功能，我作爲參數傳遞：

public object GetEmployeeBasicDetails(int employeeID) 
{ 
    return new { First_Name = "Mark", Middle_Initial = "W.", Last_Name = "Rooney"}; 
} 

我收到此錯誤：

Overloaded method has some invalid arguments.

UPDATE

這是我如何管理來解決這個問題：

public static class RequestHandler 
{ 
    public enum EmployeeRequests { BasicDetails = 0, DependentsAndEmergencyContacts = 1 , MedicalHistory = 2 } 

    private static Dictionary<EmployeeRequests, Func<object>> handlers = new Dictionary<EmployeeRequests, Func<object>>(); 

    public static void InitializeHandler(int employeeID) 
    { 
     Func<object> EmpBasicDetails = delegate { return EmployeeManagement.GetEmployeeBasicDetails(0); }; 
     AddHandler(EmployeeRequests.BasicDetails, EmpBasicDetails); 
    } 

    private static void AddHandler(EmployeeRequests caseValue, Func<object> empBasicAction) 
    { 
     handlers.Add(caseValue, empBasicAction); 
    } 

    public static void RemoveHandler(int caseValue) 
    { 
     var value = (EmployeeRequests)Enum.Parse(typeof(EmployeeRequests), caseValue.ToString()); 
     handlers.Remove(value); 
    } 

    public static object ExecuteHandler(int actualValue) 
    {   
     var request = (EmployeeRequests)Enum.Parse(typeof(EmployeeRequests), actualValue.ToString()); 
     return handlers[(EmployeeRequests)request](); 
    } 
} 

Answer 1

你不能傳遞一個返回值的方法作爲Action，因爲Action<T>必須採取參數T和返回任何結果（即void）。

您可以解決此通過傳遞調用你的方法，而忽略它的輸出拉姆達：你在哪裏得到的錯誤

Action empBasicAction =() => GetEmployeeBasicDetails(0);