當出現循環時檢測到

Question

任何人都可以請幫忙，因爲我在這裏遇到了一堵牆，我該如何檢測何時由於無效值而跳出循環。

例如，如果某人輸入年齡3 5 6 7 9，那麼孩子就沒事了，如果輸入o 3 5 6 7，這將在我的代碼中返回-1並退出循環。

如何檢測並返回消息

public static int IntIsValid(string p) 
     { 
      int pn; 
      bool isNum = int.TryParse(p, out pn); 
      int pnIsvalid = isNum ? pn : -1; 
      return pnIsvalid; 
     } 

string addDash = Regex.Replace(agesOfChildren, " ", "_"); 
      string[] splitNumberOfChildren = addDash.Split('_'); 
      string splitChildrensAge  = string.Empty; 
      int checkAgeOfChildren   = 0; 
      string problem = string.Empty; 
      foreach (var splitAgeOfChild in splitNumberOfChildren) 
      { 
       splitChildrensAge   = splitAgeOfChild; 
       checkAgeOfChildren   = RemoveInvalidInput.IntIsValid(splitChildrensAge); 
       if (checkAgeOfChildren == -1) 
       { 
        problem = "problem with age, stop checking"; 
        break; 
       } 
      } 

所以，我願意這樣做soemthing像

if(error with loop == true) 
{ 
ViewBag.Message = problem; 
} 

希望有人能幫助，因爲我已經是一片空白

喬治

Answer 1

很簡單，您已經自己給出答案：

boolean error_with_loop = false; 
foreach (var splitAgeOfChild in splitNumberOfChildren) { 
     splitChildrensAge   = splitAgeOfChild; 
     checkAgeOfChildren   = RemoveInvalidInput.IntIsValid(splitChildrensAge); 
     if (checkAgeOfChildren == -1) 
     { 
      error_with_loop = true; 
      problem = "problem with age, stop checking"; 
      break; 
     } 
} 

if (error_with_loop) { 
    ViewBag.Message = problem; 
} 

或者你拋出一個Exception：

try { 
    foreach (var splitAgeOfChild in splitNumberOfChildren) { 
      splitChildrensAge   = splitAgeOfChild; 
      checkAgeOfChildren   = RemoveInvalidInput.IntIsValid(splitChildrensAge); 
      if (checkAgeOfChildren == -1) 
      { 
       // note: no need to break 
       throw new ErrorWithLoopException(); 
      } 
    } 
} catch (ErrorWithLoopException e) { 
    ViewBag.Message = problem; 
} 

事實上，你似乎使用某種整數驗證。該Int32類具有覆蓋着的例外：http://msdn.microsoft.com/en-us/library/system.int32.parse%28v=vs.71%29.aspx您的代碼實際上是短（不知道這是否是適用的，因爲我不知道您的驗證碼不另計）：

try { 
    foreach (var splitAgeOfChild in splitNumberOfChildren) { 
      splitChildrensAge   = splitAgeOfChild; 
      checkAgeOfChildren   = Int32.Parse(splitChildrensAge); 
    } 
} catch (FormatException e) { 
    ViewBag.Message = problem; 
} 

Answer 2

你可以扔一個例外（取決於你的程序的設計），或者你可以設置一個標誌。

bool success = true; 

foreach (var splitAgeOfChild in splitNumberOfChildren) 
{ 
     splitChildrensAge = splitAgeOfChild; 
     checkAgeOfChildren = RemoveInvalidInput.IntIsValid(splitChildrensAge); 
     if (checkAgeOfChildren == -1) 
     { 
      problem = "problem with age, stop checking"; 
      success = false; // change the flag 
      break; 
     } 
} 

或使用異常（我用ArgumentOutOfRangeException在這裏，但你可以創建你自己的）：

foreach (var splitAgeOfChild in splitNumberOfChildren) 
{ 
     splitChildrensAge = splitAgeOfChild; 
     checkAgeOfChildren = RemoveInvalidInput.IntIsValid(splitChildrensAge); 
     if (checkAgeOfChildren == -1) 
     { 
      problem = "problem with age, stop checking"; 
      throw new ArgumentOutOfRangeException("Age", problem); 
     } 
} 

Answer 3

爲什麼don'y你只是檢查string.Empty在結束了嗎？如果你有一個錯誤，只會設置：

if (!string.IsNullOrEmpty(problem)) 
{ 
    ViewBag.Message = problem; 
} 

Answer 4

簡單地做：

if (checkAgeOfChildren == -1) 
{ 
    problem = "problem with age, stop checking"; 
    break; 
} 

if (!string.IsNullOrEmpty(problem)) { 
    ViewBag.Message = problem; 
} 

您也可以拋出異常：

try { 
    if (checkAgeOfChildren == -1) 
    { 
     throw new ArgumentException("Invalid Argument"); 
    } catch (ArgumentException e) 
    { 
     ViewBag.Message = e.Message; 
    } 
} 

ArgumentException可以用更合適的替代或自定義異常。

Answer 5

爲什麼不能在循環裏是這樣的：

if (checkAgeOfChildren == -1) 
       { 
        ViewBag.Message = "problem with age, stop checking"; 
        break; 
       }