如何確定哪個元素導致溢出？

Question

我有這樣的代碼：

String testData = File.ReadAllText("siteQueryTest.txt"); 
XDocument xmlDoc = XDocument.Parse(testData); 
List<SiteQuery> sitequeries = 
(from sitequery in xmlDoc.Descendants("SiteQuery") 
    select new SiteQuery 
    { 
     Id = Convert.ToInt32(sitequery.Element("Id").Value), 
     UPCPackSize = Convert.ToInt32(sitequery.Element("UPCPackSize").Value), 
     UPC_Code = sitequery.Element("UPC_Code").Value, 
     crvId = sitequery.Element("crvId").Value, 
     dept = Convert.ToInt32(sitequery.Element("dept").Value), 
     description = sitequery.Element("description").Value, 
     openQty = Convert.ToDouble(sitequery.Element("openQty").Value), 
     packSize = Convert.ToInt32(sitequery.Element("packSize").Value), 
     subDept = Convert.ToInt32(sitequery.Element("subDept").Value), 
     unitCost = Convert.ToDecimal(sitequery.Element("unitCost").Value), 
     unitList = Convert.ToDecimal(sitequery.Element("unitList").Value), 
     vendorId = sitequery.Element("vendorId").Value, 
     vendorItem = sitequery.Element("vendorItem").Value, 
    }).ToList<SiteQuery>(); 

TESTDATA是：

<SiteQueries><SiteQuery><Id>00006000002</Id><UPCPackSize>1</UPCPackSize><UPC_Code>00006000002</UPC_Code><crvId></crvId><dept>8</dept><description>ZZ</description><openQty>0.0</openQty><packSize>1</packSize><subDept>80</subDept><unitCost>1.25</unitCost><unitList>5.0</unitList><vendorId>CONFLICT</vendorId><vendorItem>123456</vendorItem></SiteQuery> 
. . . // gazillions of other SiteQuery "records" 
<SiteQuery><Id>5705654</Id><UPCPackSize>1</UPCPackSize><UPC_Code>5705654</UPC_Code><crvId></crvId><dept>2</dept><description>what do you want</description><openQty>0.0</openQty><packSize>1</packSize><subDept>0</subDept><unitCost>0.55</unitCost><unitList>1.62</unitList><vendorId></vendorId><vendorItem></vendorItem></SiteQuery></SiteQueries> 

，但我得到這個代碼和數據以下運行時異常：

System.OverflowException was unhandled 
    _HResult=-2146233066 
    _message=Value was either too large or too small for an Int32. 
    HResult=-2146233066 
    IsTransient=false 
    Message=Value was either too large or too small for an Int32. 
    Source=mscorlib 
    StackTrace: 
     at System.Number.ParseInt32(String s, NumberStyles style, NumberFormatInfo info) 
     at System.Convert.ToInt32(String value) 
     at Sandbox.Form1.<button56_Click>b__e(XElement sitequery) in c:\HoldingTank\Sandbox\Form1.cs:line 2041 
     at System.Linq.Enumerable.WhereSelectEnumerableIterator`2.MoveNext() 
     at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection) 
     at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source) 
    . . . 
    InnerException: 

有幾個INT值（4）在每個xml「記錄」中;有成千上萬的記錄。我怎麼能在沒有嘗試戴上一個Rainman帽子（它不適合我）的情況下確定導致溢出或下溢的問題是哪個值？

如果是下溢（msg表示異常「OverflowException」和「Value對於Int32來說太大或太小」，是否可能是由於這四個int成員之一的值爲空值？如果是這樣我怎麼能告訴它要考慮的一個空值0

Answer 1

這就是爲什麼大多數程序員最終使用擴展方法，而不是LINQ的改寫：。

private static SiteQuery ParseSiteQuery(XElement sitequery) 
{ 
    return new SiteQuery 
    { 
     Id = Convert.ToInt32(sitequery.Element("Id").Value), 
     UPCPackSize = Convert.ToInt32(sitequery.Element("UPCPackSize").Value), 
     UPC_Code = sitequery.Element("UPC_Code").Value, 
     crvId = sitequery.Element("crvId").Value, 
     dept = Convert.ToInt32(sitequery.Element("dept").Value), 
     description = sitequery.Element("description").Value, 
     openQty = Convert.ToDouble(sitequery.Element("openQty").Value), 
     packSize = Convert.ToInt32(sitequery.Element("packSize").Value), 
     subDept = Convert.ToInt32(sitequery.Element("subDept").Value), 
     unitCost = Convert.ToDecimal(sitequery.Element("unitCost").Value), 
     unitList = Convert.ToDecimal(sitequery.Element("unitList").Value), 
     vendorId = sitequery.Element("vendorId").Value, 
     vendorItem = sitequery.Element("vendorItem").Value, 
    }; 
} 

，然後做

List<SiteQuery> sitequeries = xmlDoc.Descendants("SiteQuery") 
            .Select(ParseSiteQuery).ToList(); 

現在，當發生異常時，您將在此轉換函數內部破解，其範圍爲sitequery，從而立即知道特定XElement導致失敗的原因。

然後，您可以使用quickwatch表達式快速找出初始化程序導致異常的原因。甚至爲每個屬性分配編寫單獨的語句。

Answer 2

這是結束了工作：

private void button42_Click(object sender, EventArgs e) 
    { 
     ArrayList arrList = 
    FetchSiteQuery("http://localhost:21608/api/sitequery/getall/dbill/ppus/42"); 
     String omnivore = "<SiteQueries>"; 
     foreach (String s in arrList) //- see siteQueryData.png 
     { 
      omnivore += s; 
     } 
     omnivore += "</SiteQueries>"; 

     String messedUpJunk = "<ArrayOfSiteQuery xmlns:i=\"http://www.w3.org/2001/XMLSchema- 
    instance\" xmlns=\"http://schemas.datacontract.org/2004/07/CStore.DomainModels.HHS\">"; 
     omnivore = omnivore.Replace(messedUpJunk, String.Empty); 
     omnivore = omnivore.Replace("</ArrayOfSiteQuery>", String.Empty); 

     XDocument xmlDoc = XDocument.Parse(omnivore); 
     List<SiteQuery> sitequeries = 
    xmlDoc.Descendants("SiteQuery").Select(GetSiteQueryForXMLElement).ToList(); 
    } 

    private static SiteQuery GetSiteQueryForXMLElement(XElement sitequery) 
    { 
     return new SiteQuery 
     { 
      Id = sitequery.Element("Id").Value, 
      UPCPackSize = Convert.ToInt32(sitequery.Element("UPCPackSize").Value), 
      UPC_Code = sitequery.Element("UPC_Code").Value, 
      crvId = sitequery.Element("crvId").Value, 
      dept = Convert.ToInt32(sitequery.Element("dept").Value), 
      description = sitequery.Element("description").Value, 
      openQty = Convert.ToDouble(sitequery.Element("openQty").Value), 
      packSize = Convert.ToInt32(sitequery.Element("packSize").Value), 
      subDept = Convert.ToInt32(sitequery.Element("subDept").Value), 
      unitCost = Convert.ToDecimal(sitequery.Element("unitCost").Value), 
      unitList = Convert.ToDecimal(sitequery.Element("unitList").Value), 
      vendorId = sitequery.Element("vendorId").Value, 
      vendorItem = sitequery.Element("vendorItem").Value, 
     }; 
    }