小编Key*_*dly的帖子

我有一个SQL Server程序我正在访问Linq到Sql.当我执行查询时,我收到错误"查询结果不能多​​次枚举".该参数在txtName文本框中输入,结果显示在lstName列表视图中.

 public void GetSearchString()
 {
     Data.Database.FRCDatabaseDatacontext context = 
         new Data.Database.FRCDatabaseDatacontext();
     var result = context.GetSearchProcedure(txtName.Text);
     foreach (GetSearchProcedureResult search in result)
         if ( search.UserGuid == 
               Workspace.Instance.ActiveUser.CurrentUserActiveDirectoryGuid)
         {
             lstName.ItemsSource = result.ToList();
         }
 }

此方法将返回每个结果,但我想返回guids匹配的结果.

谢谢!

Data.Database.FRCDatabaseDatacontext context = 
    new Data.Database.FRCDatabaseDatacontext();
var result = context.GetSearchProcedure(txtName.Text);
lstName.ItemsSource = result.ToList();

对于桥牌表,我从其他2个表中获得了PK.为桥表制作PK字段或在两个字段之间制作复合/复合的优缺点是什么.

我想确保遵循最佳做法.

我正在阅读的一些链接:

https://dba.stackexchange.com/questions/3134/in-sql-is-it-composite-or-compound-keys

http://social.msdn.microsoft.com/Forums/en-US/sqlgetstarted/thread/9d3cfd17-e596-4411-b3d8-66e0ec8bfdc7/

http://www.ben-morris.com/identity-surrogate-vs-composite-keys-in-sql-server

复合主键与唯一对象ID字段

在下面的代码中,文件保存在项目的debug文件夹中,我想将文件存储在通用指定文件夹下的appdata文件夹中!

AViewModel vm = DataContext as AViewModel;
var table = vm.FileSelectedItem;

if (table != null)
{
    var filename = System.IO.Path.GetTempFileName();
    File.WriteAllBytes(table.FileTitle, table.Data);
    Process prc = new Process();
    prc.StartInfo.FileName = table.FileTitle;
    prc.Start();
}  

//table.FileTitle is the name of the file stored in the db 
//    eg:(test1.docx, test2.pdf, test3.txt, test4.xlsx)
//table.Data is public byte[] Data { get; set; } property
//    which stores the files coming from the db.

我正在看GetFolderPath并尝试这样的事情

System.IO.Path.GetTempFileName(
    Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData));

谢谢你的回复!

在Linq或Linq to Sql更准确:是那里的之间的差异== null和IsNullOrEmpty在下面的查询？

From a in context.SomeTable
where a.SomeId.Equals(SomeOtherId)
&& a.SomeOtherColumn == null
Select new .....

&

From a in context.SomeTable
where a.SomeId.Equals(SomeOtherId)
&& string.IsNullOrEmpty(a.SomeOtherColumn)
Select new .....