返回空值時如何處理空數據

Question

我有下面的代碼爲我返回數據。如果結果等於「成功」，那麼就有數據。我沒有收到任何數據 但返回null。數據顯示在網格上，當webgrid發現數據爲空時，頁面崩潰。

我該如何處理null？

 public Chemicalsdetails GetChemicalDataGeneratedForMonth(string branchcode, string departmentnumber, string previousMonth, string currentMonth) 
      { 
       string result = string.Empty; 
       result = _chemmeterprocessor.CopyPreviousMonthData(branchcode, departmentnumber, previousMonth, currentMonth); 
       Chemicalsdetails objChem = null; 

       if (result == "Success") 
       { 
        objChem = new Chemicalsdetails(); 
        List<Chemicaltransactiondto> objAllData = new List<Chemicaltransactiondto>(); 
        objAllData = _chemmeterprocessor.GetAllChemicalEntries(branchcode, departmentnumber, currentMonth); 
        objChem.GetAllChemicalsInformation = objAllData;     
       } 
       else 
       { 
        Chemicalsdetails objNoData = new Chemicalsdetails();     
       } 

       return objChem; 
      } 

Answer 1

檢索您的數據後檢查null。

 public Chemicalsdetails GetChemicalDataGeneratedForMonth(string branchcode, string departmentnumber, string previousMonth, string currentMonth) 
      { 
       string result = string.Empty; 
       result = _chemmeterprocessor.CopyPreviousMonthData(branchcode, departmentnumber, previousMonth, currentMonth); 
       Chemicalsdetails objChem = null; 

       List<Chemicaltransactiondto> objAllData = new List<Chemicaltransactiondto>(); 

       //****Check for "Success" 
       if (result == "Success") 
       { 
        //****Retrieve chemical data 
        objAllData = _chemmeterprocessor.GetAllChemicalEntries(branchcode, departmentnumber, currentMonth); 
        //****End Retrieve chemical data 
       } 

       //****Check for non-null data. 
       if ((result == "Success") && (objAllData!=null)) 
       { 
        objChem = new Chemicalsdetails(); 

        objChem.GetAllChemicalsInformation = objAllData;     
       } 
       else 
       { 
        Chemicalsdetails objNoData = new Chemicalsdetails();     
       } 

       return objChem; 
      }