C＃中使用LINQ to选择行的最大ID [英] C# Using LINQ to select max ID of row

问题描述

我有一个面包屑表，我要返回最近一次插入的行。在SQL这将是一个 MAX（）的功能，但不知道如何做LINQ的等价物。基本上我想选择具有最高 BreadCrumbID WHERE专案编号= 49 的行。

下面的查询我现在将选择所有的行 WHERE专案编号= 49 。我要选择具有最高 BreadCrumbID 。

谢谢！

行

代码：

 使用（dbPSREntities5 myEntities =新dbPSREntities5（））
 {
 VAR currentStatus =（从tbBreadCrumb在myEntities.tbBreadCrumbs.Where（X => x.ProjectID == 49）
选择新的
 {
状态= tbBreadCrumb.BreadCrumbID，
}）; 
} 
  

解决方案

试试这个：

 使用（dbPSREntities5 myEntities =新dbPSREntities5（））
 {
 VAR currentStatus =（从tbBreadCrumb在myEntities.tbBreadCrumbs 。凡（X => x.ProjectID == myEntities.tbBreadCrumbs.Max（b = GT; b.ProjectId））
选择新的
 {
状态= tbBreadCrumb.BreadCrumbID，
}）; 
 
} 
  

I have a breadcrumb table and I want to return the row that was most recently inserted. In SQL it would be a MAX() function but not sure how to do the equivalent in LINQ. Basically I want to select the row that has the highest BreadCrumbID WHERE ProjectID = 49.

Here's the query I have right now that would select all rows WHERE ProjectID = 49. I want to select the row that has the highest BreadCrumbID.

Thanks!

Code:

using (dbPSREntities5 myEntities = new dbPSREntities5())
{
   var currentStatus = (from tbBreadCrumb in myEntities.tbBreadCrumbs.Where(x => x.ProjectID == 49)
                        select new
                        {
                           Status = tbBreadCrumb.BreadCrumbID,
                        });
}

解决方案

try this:

using (dbPSREntities5 myEntities = new dbPSREntities5())
    {
        var currentStatus = (from tbBreadCrumb in myEntities.tbBreadCrumbs.Where(x => x.ProjectID == myEntities.tbBreadCrumbs.Max(b=>b.ProjectId))
                              select new
                              {
                                  Status = tbBreadCrumb.BreadCrumbID,
                              });

    }

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