C#：如何从 linq 查询设置组合框 valuemember

发布于 2024-11-08 02:48:10 字数 644 浏览 0 评论 0原文

好的，所以我有组合框，其数据源是 linq 查询的结果。

//load QA names
            var qaNames =
                from a in db.LUT_Employees
                where a.position == "Supervisor" && a.department == "Quality Assurance"
                select new { a, Names = a.lastName + ", " + a.firstName };

            cboQASupervisor.DataSource = qaNames;
            cboQASupervisor.DisplayMember = "Names";

我遇到的问题是，当我尝试添加下一行代码时

cboQASupervisor.ValueMember = "ID";

，我在运行时收到错误，~~它无法转换匿名类型。我该如何解决这个问题？~~

更正：错误是：

无法绑定到新值成员。参数名称：值

原文

ok so i have combobox whos datasource are the results of a linq query

//load QA names
            var qaNames =
                from a in db.LUT_Employees
                where a.position == "Supervisor" && a.department == "Quality Assurance"
                select new { a, Names = a.lastName + ", " + a.firstName };

            cboQASupervisor.DataSource = qaNames;
            cboQASupervisor.DisplayMember = "Names";

The problem im having is when i try to add the next line of code

cboQASupervisor.ValueMember = "ID";

I get an error on runtime that ~~it couldn't cast the anonymous type.~~ How do i fix this?

Correction:
The error is:

Cannot bind to the new value member.
Parameter name: value

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一梦等七年七年为一梦 2024-11-15 02:48:10

您指定 ID 作为值字段，但匿名类型中没有 ID 属性。
假设您的 LUT_Employees 对象中有 ID：

var qaNames = (
    from a in db.LUT_Employees
    where a.position == "Supervisor" && a.department == "Quality Assurance"
    select new { a.ID, Names = a.lastName + ", " + a.firstName })
    .ToList();

cboQASupervisor.DataSource = qaNames;
cboQASupervisor.DisplayMember = "Names";
cboQASupervisor.ValueMember = "ID";

You specify ID as the value field, but you don't have ID property in your anonymous type.
Assuming you have ID in your LUT_Employees object:

var qaNames = (
    from a in db.LUT_Employees
    where a.position == "Supervisor" && a.department == "Quality Assurance"
    select new { a.ID, Names = a.lastName + ", " + a.firstName })
    .ToList();

cboQASupervisor.DataSource = qaNames;
cboQASupervisor.DisplayMember = "Names";
cboQASupervisor.ValueMember = "ID";

回复收藏 0 原文

じ违心 2024-11-15 02:48:10

您可以尝试以下操作：

       var qaNames =
       from a in db.LUT_Employees
       where a.position == "Supervisor" && a.department == "Quality Assurance"
        select new { Id = a.ID,  Names = a.lastName + ", " + a.firstName };

        cboQASupervisor.DataSource = qaNames.ToList();
        cboQASupervisor.DisplayMember = "Names";
        cboQASupervisor.ValueMember = "Id";

将 .ToList() 添加到数据源行中的代码中。

You can try this:

       var qaNames =
       from a in db.LUT_Employees
       where a.position == "Supervisor" && a.department == "Quality Assurance"
        select new { Id = a.ID,  Names = a.lastName + ", " + a.firstName };

        cboQASupervisor.DataSource = qaNames.ToList();
        cboQASupervisor.DisplayMember = "Names";
        cboQASupervisor.ValueMember = "Id";

Add .ToList() to your code in the datasource line.

回复收藏 0 原文

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