c# - 使用 LINQ 从 DataTable 获取不同的项目

Question

我在 DataTable 中返回数据，如下所示:

Department | EmployeeName

1 | Employee1

1 | Employee1

2 | Employee2

3 | Employee3

3 | Employee3

3 | Employee3

我试图只获取不同的行并将其放入集合中，如下所示:

IEnumerable<Department> departments = dt.AsEnumerable().Select(row =>
    new Department
        {
            DepartmentID = Int32.Parse(row["DepartmentID"].ToString()),
            Employee = new Employee { EmployeeName = row["EmployeeName"].ToString() }
        }).Distinct();

它应该只返回 3 行，但实际上却返回了全部 6 行。

我在这里做错了什么？

Answer 1

不确定，但以下之一可能适合您.......

就这样做

var distrows= table1.AsEnumerable().Distinct();

将完成您的任务......而不是从distrow创建部门集合..

IEnumerable<Department> departments = (from DataRow dRow in distrows   
                         new Department
        {
            DepartmentID = Int32.Parse(row["DepartmentID"].ToString()),
            Employee = new Employee { EmployeeName = row["EmployeeName"].ToString() }
        });

或

var distinctRows = (from DataRow dRow in dTable.Rows
            select new {col1=dRow["dataColumn1"],col2=dRow["dataColumn2"]}).Distinct();


IEnumerable<Department> departments = (from DataRow dRow in distrows   
                             new Department
            {
                DepartmentID = Int32.Parse(distinctRows.col1),
                Employee = new Employee { EmployeeName = distinctRows.col2.ToString() }
            });