.NET的值类型和引用类型
先看下微软官方介绍:
如果数据类型在它自己的内存分配中存储数据，则该数据类型就是“值类型”。“引用类型”包含指向存储数据的其他内存位置的指针。
以下编程元素未限定为类型，因为您无法将它们中的任何一个指定为声明元素的数据类型：
-
命名空间
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模块
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事件
-
属性和过程
-
变量、常数和字段
如果如下这样是值类型;
int i = 10;
int j = i;
i++;
Console.Write(i);
Console.Write(j);
i的值是11,j的值是10;
如下这样DataTable传递是引用类型:
/// <summary>
///
/// </summary>
/// <param name="dtOriginalData"></param>
/// <returns></returns>
protected override DataTable TransferData(DataTable dtOriginalData)
{
DataTable dtFinalData = null;
try
{
DataTable dtFolderData = base.ExcuteOracleReader(GetSqlQueryGetFolder);
dtQARelate = base.ExcuteOracleReader(GetQARelateSql);
if (dtOriginalData != null && dtOriginalData.Rows.Count > 0)
{
dtFinalData = dtOriginalData.Copy();
AddGlossaryToDataTable(dtFinalData);
AddReferencesToDataTable(dtFinalData);
AddImageUrlToDataTable(dtFinalData);
TransforFolderData(dtFolderData, base.SiteUrl);
AddProductCatagory(dtFinalData, dtFolderData);
this.ChangeFieldName(dtFinalData);
}
}
catch (Exception ex)
{
}
return dtFinalData;
}
private void AddImageUrlToDataTable(DataTable dtFinalData)
{
DataTable dtImageUrl = base.ExcuteOracleReader(GetAnswerSummarySql);
foreach (DataRow dr in dtFinalData.Rows)
{
if (dtImageUrl != null && dtImageUrl.Rows.Count > 0)
{
string ID = dr["ID"].ToString();
DataRow[] newdrs = dtImageUrl.Select(string.Format("ID='{0}'", ID));
dr[this.ORACLE_FIELD_ANSWER_DETAIL] += GetImageUrl(newdrs);
}
}
if (dtImageUrl != null && dtImageUrl.Rows.Count > 0)
{
dtImageUrl.Dispose();
dtImageUrl.Clear();
}
}
private string GetImageUrl(DataRow[] drs)
{
string strImageUrl = "";
if (drs != null && drs.Count() > 0)
{
string NewUrl = "";
string ImageUrl = "<src img=\"{0}\"/>";
foreach (DataRow dr in drs)
{
if (dr[this.ORACLE_FIELD_ANSWER_ImageURL] != null && !string.IsNullOrEmpty(dr[this.ORACLE_FIELD_ANSWER_ImageURL].ToString()))
{
NewUrl = dr[this.ORACLE_FIELD_ANSWER_ImageURL].ToString();
strImageUrl += "<br />" + string.Format(ImageUrl, NewUrl);
}
}
}
return strImageUrl;
}
protected override List<SingleResultBE> ModifyQARelateAndRelateBy(List<SingleResultBE> newlistResult)
{
List<SingleResultBE> onelistResult = new List<SingleResultBE>();
foreach (SingleResultBE entity in newlistResult)
{
if (!string.IsNullOrEmpty(entity.Id) && !string.IsNullOrEmpty(entity.ListItemId.ToString()))
{
DataRow[] newdrs = dtQARelate.Select(string.Format("ID='{0}'", entity.Id));
if (newdrs != null && newdrs.Count() > 0)
entity.QARelate = GetQARelate(newdrs, newlistResult);
DataRow[] otherdrs = dtQARelate.Select(string.Format("RELATEID='{0}'", entity.Id));
if (otherdrs != null && otherdrs.Count() > 0)
entity.RelateBy = GetQARelateBy(otherdrs, newlistResult);
onelistResult.Add(entity);
}
}
if (dtQARelate != null && dtQARelate.Rows.Count > 0)
{
dtQARelate.Dispose();
dtQARelate.Clear();
}
return onelistResult;
}
#endregion
#region Private Methods
private string GetQARelateBy(DataRow[] drs, List<SingleResultBE> newlistResult)
{
string strQARelateBy = "";
foreach (DataRow dr in drs)
{
string strQARelateID = "";
string strTitle = "";
if (dr[this.ORACLE_FIELD_ID] != null)
strQARelateID = dr[this.ORACLE_FIELD_ID].ToString();
if (dr[this.ORACLE_FIELD_TITLE] != null)
{
strTitle = dr[this.ORACLE_FIELD_TITLE].ToString();
}
List<SingleResultBE> needlistfolder = new List<SingleResultBE>();
if (!string.IsNullOrEmpty(strTitle) && !string.IsNullOrEmpty(strQARelateID))
needlistfolder = GetlistResult(newlistResult, strTitle, strQARelateID);
if (needlistfolder != null && needlistfolder.Count > 0)
{
strQARelateBy += GetlistItemGuid(needlistfolder[0].ListItemGuid);
}
}
return strQARelateBy;
}
private string GetQARelate(DataRow[] drs, List<SingleResultBE> newlistResult)
{
string strQARelate = "";
foreach (DataRow dr in drs)
{
string strQARelateID = "";
string strTitle = "";
if (dr[this.ORACLE_FIELD_QARELATEDID] != null)
strQARelateID = dr[this.ORACLE_FIELD_QARELATEDID].ToString();
if (dr[this.ORACLE_FIELD_QARELATED_TITLE] != null)
strTitle = dr[this.ORACLE_FIELD_QARELATED_TITLE].ToString();
List<SingleResultBE> needlistfolder = new List<SingleResultBE>();
if (!string.IsNullOrEmpty(strTitle) && !string.IsNullOrEmpty(strQARelateID))
needlistfolder = GetlistResult(newlistResult, strTitle, strQARelateID);
if (needlistfolder != null && needlistfolder.Count > 0)
{
strQARelate += GetlistItemGuid(needlistfolder[0].ListItemGuid);
}
}
return strQARelate;
}
private void AddProductCatagory(DataTable dtFinalData, DataTable dtFolderData)
{
dtFinalData.Columns[this.ORACLE_FIELD_PRODUCT_CATEGORY].MaxLength = 99999;
foreach (DataRow dr in dtFinalData.Rows)
{
if (dtFolderData != null && dtFolderData.Rows.Count > 0)
{
string ID = dr["ID"].ToString();
DataRow[] newdrs = dtFolderData.Select(string.Format("ID='{0}'", ID));
dr[this.ORACLE_FIELD_PRODUCT_CATEGORY] = GetProductCatagory(newdrs, dtFolderData);
}
}
}
private string GetProductCatagory(DataRow[] drs, DataTable dtFolderData)
{
List<SingleResultBE> listResult = new List<SingleResultBE>();
listResult.AddRange(HavelistResult);
string strProductCatagory = "";
if (drs != null && drs.Count() > 0)
{
foreach (DataRow dr in drs)
{
string foldername = "";
string folderID = "";
string ID = "";
if (dr[this.ORACLE_FIELD_FOLDERID] != null)
folderID = dr[this.ORACLE_FIELD_FOLDERID].ToString();
DataRow[] drfolders = dtFolderData.Select(string.Format("FOLDERID='{0}'", folderID));
List<SingleResultBE> needlistfolder = new List<SingleResultBE>();
foreach (DataRow drf in drfolders)
{
List<SingleResultBE> Islistfolder = new List<SingleResultBE>();
foldername = drf[this.ORACLE_FIELD_FATHERTITLE].ToString();
ID = drf[this.ORACLE_FIELD_FOLDERID].ToString();
if (!string.IsNullOrEmpty(ID))
{
Islistfolder = GetlistResult(listResult, foldername, ID);
if (Islistfolder != null && Islistfolder.Count() > 0)
needlistfolder.AddRange(Islistfolder);
}
if (needlistfolder.Count > 0)
needlistfolder = needlistfolder.Distinct().ToList();
}
if (needlistfolder != null && needlistfolder.Count > 0)
{
foreach (SingleResultBE entity in needlistfolder)
{
strProductCatagory += GetlistItemGuid(entity.ListItemGuid.ToString());
}
}
}
}
return strProductCatagory;
}
private string GetlistItemGuid(string itemguid)
{
if (!string.IsNullOrEmpty(itemguid))
{
int startindex = itemguid.IndexOf(startwith) + 1;
int endindex = itemguid.IndexOf(endwith);
return itemguid.Substring(startindex, endindex - startindex).ToLower() + ";#";
}
return null;
}
private List<SingleResultBE> GetlistResult(List<SingleResultBE> listResult, string title, string ID)
{
List<SingleResultBE> needlistfolder = new List<SingleResultBE>();
if (!string.IsNullOrEmpty(title))
{
needlistfolder = (from entity in listResult
where entity.Title == title && entity.Id == ID
select entity).ToList();
}
return needlistfolder;
}
还有如下也是引用类型:
///新建一个类
public class FolderBE
{
public string FolderOne
{ get; set; }
public string FolderTwo
{ get; set; }
public string FolderThree
{ get; set; }
public string FolderFour
{ get; set; }
public string FolderFive
{ get; set; }
}
//然后:
List<FolderBE> listFolder = new List<FolderBE>();
FolderBE folder = new FolderBE();
folder.FolderOne = "one";
folder.FolderTwo = "two";
folder.FolderThree = "three";
listFolder.Add(folder);
folder.FolderFour = "four";
///然后listFolder里的一条数据的FolderFour也会变成"four";
/// 所以我们在使用它时要这样:
List<FolderBE> listFolder = new List<FolderBE>();
FolderBE folder = new FolderBE();
folder.FolderOne = "one";
folder.FolderTwo = "two";
folder.FolderThree = "three";
listFolder.Add(folder);
folder = new FolderBE();
folder.FolderOne = "one";
folder.FolderTwo = "two";
folder.FolderThree = "three";
folder.FolderFour = "four";
///listFolder里面的数据 FolderFour不会变成"four"
先写到这里吧.
