注意看以下LINQ的寫法.

var modeltest1 = db.SysUsers.Where(m => m.State != 0

&& string.IsNullOrEmpty(User_Name) ? true : m.Name.Contains(User_Name));

var modeltest2 = db.SysUsers.Where(m => m.State != 0

&& (string.IsNullOrEmpty(User_Name) ? true : m.Name.Contains(User_Name)));

var modeltest3 = db.SysUsers.Where(m =>

string.IsNullOrEmpty(User_Name) ? true : m.Name.Contains(User_Name)

&& m.State != 0);

var modeltest4 = db.SysUsers.Where(m =>

(string.IsNullOrEmpty(User_Name) ? true : m.Name.Contains(User_Name))

&& m.State != 0); 

系統翻譯為

Modeltest1

SELECT  *

FROM    [dbo].[SysUser] AS [Extent1]