Question

您好，我正在尝试通过ID检索特定部门。

这是我的代码

public void GetDeptId(int _DeptID)
{
var dept = dbContext.tblDepartments
    .Select(d => new Department
    {
        DepartmentID = d.DepartmentID,
        DepartmentName = d.DepartmentName
    }).Where(d => d.DepartmentID == _DeptID);
}

如何根据_DeptID过滤结果集？即使记录存在，也不会返回任何记录。

Answer 1

执行以下操作：

  public ICollection<Department> GetDeptId(int _DeptID)
{
var dept = dbContext.tblDepartments
    .Select(d => new Department
    {
        DepartmentID = e.DepartmentID,
        DepartmentName = e.DepartmentName
    }).Where(c => c.DepartmentID == _DeptID).ToList();
 return dept;
}

Answer 2

您是否需要Select子句？如果您只需要找一个部门，则可以执行以下操作：

public void GetDeptId(int _DeptID)
{
    var depts = dbContext.tblDepartments
                        .Where(d => d.DepartmentID == _DeptID);
}

或者，如果只是一个，那就有意义了：

public void GetDeptId(int _DeptID)
{
    var dept = dbContext.tblDepartments
                        .First(d => d.DepartmentID == _DeptID);
}

Answer 3

请尝试这个。

var dept = dbContext.tblDepartments.Where(d => d.DepartmentID == _DeptID)
    .Select(d => new Department
    {
        DepartmentID = d.DepartmentID,
        DepartmentName = d.DepartmentName
    });
}

C＃Linq查询问题

3 个答案: