在TryGetValue字典中，如果它是類的一部分，我該如何編寫out參數（並獲取它的值）？

Question

過去的問題線程，並鏈接到fullpast代碼HERE

創建我有一個類字典參數，因此它可以容納兩個string值。現在我想要寫的字符串TryGetValue到out都在這個類：

public class DictionaryInitializer 
{ 
    public class DictionarySetup 
    { 
     public string theDescription { get; set; } 
     public string theClass { get; set; } 
    } 

正如你所看到的，有嵌套在DictionarySetuptheDescription和theClass。然後我會在這裏使用該類創建字典：

public class DictionaryInit 
    { 
     //IS_Revenues data 
     public Dictionary<int, DictionarySetup> accountRevenue = new Dictionary<int, DictionarySetup>() 
      { 
       { 400000, new DictionarySetup {theDescription="Call", theClass="Revenues"}} 
      }; 
     public Dictionary<int, DictionarySetup> accountExpenses = new Dictionary<int, DictionarySetup>() 
      { 
       {790100, new DictionarySetup { theDescription="Currency Hedge", theClass="Other income/expense"}} 
      }; 
    } 

然後，在我計劃在字典用我TryGetValue我的擴展方法：

public void DictionaryUseKey(int MapCode, int MapKey, int rowindex, Dictionary<int, DictionarySetup> AccountLexicon) 
    { 
     AccountLexicon[1] = new DictionarySetup(); 
     DictionarySetup Classes; 
     DictionarySetup Descriptions; 
     //Saw the above code in another thread, not sure if it's what I should be doing but it seems pretty close to what I want, however, I don't know how to specify the DictionarySetup.theDescription for example; 
     AccountLexicon.TryGetValue(MapKey, out Classes); 
     { 
      //I want to be able to write theDescription and theClass into string variables for use below if the `TryGetValue` returns true, but it seems to me that it can only out one value? How does this work? 
      DGVMain.Rows[rowindex].Cells[3].Value = ?? how do I write something like... theValues.theDescription; 
      DGVMain.Rows[rowindex].Cells[11].Value = ?? how do I write something like... theValues.theClass; 
     } 
    } 

最後，我呼籲在擴展方法我事件像這樣：

private void btnMapper_Click(object sender, EventArgs e) 
    { 
     for (int rowindex = 0; rowindex < DGVMain.RowCount; rowindex++) 
     { 
      int accountKey = Convert.ToInt32(DGVMain.Rows[rowindex].Cells[2].Value); 
      int projCode = Math.Abs(Convert.ToInt32(DGVMain.Rows[rowindex].Cells[7].Value)); 
      int deptCode = Math.Abs(Convert.ToInt32(DGVMain.Rows[rowindex].Cells[9].Value)); 
      int AbsoluteKey = Math.Abs(accountKey); 
      while (AbsoluteKey >= 10) { AbsoluteKey /= 10; } 
      while (deptCode >= 10) { deptCode /= 10; } 
      theDictionary = new DictionaryInit(); 
      DictionaryUseKey(deptCode, accountKey, theDictionary.accountRevenue); 
     } 
    } 

Answer 1

其實TryGetValue方法返回一個布爾值表示指定鍵的存在，如果鍵被找到時，科爾esponding的值將被存儲在out參數中。在你的情況下，out參數是Classes，在你的代碼中定義如下：DictionarySetup Classes。這意味着如果鑰匙出現在字典中意味着相應的DictionarySetup對象將被存儲在Classes中，因此您可以從Classes訪問theDescription和theClass;考慮下面的代碼：

if(AccountLexicon.TryGetValue(MapKey, out Classes)) 
{ 
    DGVMain.Rows[rowindex].Cells[3].Value = Classes.theDescription; 
    DGVMain.Rows[rowindex].Cells[11].Value = Classes.theClass; 
}