Question

using (SmartEntities employeeverificationcontext = new SmartEntities())
{
    Employee emp = (from c in employeeverificationcontext.EmployeeEntity 
                    where c.Employee_ID == emp_detail.EmployeeID 
                    select new Employee {c.Status}).FirstOrDefault();
    emp.Status = emp_detail.Status;
    int i=employeeverificationcontext.SaveChanges();
    if (i > 0)
    {
        result = "Verification Process Completed";
    }
}

错误：错误1无法使用集合初始值设定项初始化类型'SmartWCF.Employee'，因为它没有实现'System.Collections.IEnumerable'**

Answer 1

您应该选择当前对象（select new Employee {c.Status}）

而不是c

所以你的查询应该是：

Employee emp = (from c in employeeverificationcontext.EmployeeEntity 
               where c.Employee_ID == emp_detail.EmployeeID 
               select c).FirstOrDefault();

或

Employee emp = employeeverificationcontext.EmployeeEntity
                      .FirstOrDefault(c=> Employee_ID == emp_detail.EmployeeID);

Answer 2

只选择Status，如下所示：

var employeeStatus = (from c in employeeverificationcontext.EmployeeEntity 
                        where c.Employee_ID == emp_detail.EmployeeID 
                      select c.Status).FirstOrDefault();

但是如果您想将其设置为新状态并将其保存到数据上下文中，这对您没有帮助。在这种情况下，您必须选择Employee。

本文中提到了一些替代方案：How to update a single column in LINQ without loading the entire row?

LINQ to Entity选择查询错误

2 个答案: