结合1的SelectList 2实体框架模型领域？ [英] Combine 2 Entity Framework Model fields in 1 SelectList?

问题描述

我试图显示从的SelectList内我的 INV_Locations 模型2个字段： location_dept | location_room 或例如 IT |存储。使用<一个href=\"https://stackoverflow.com/questions/2758734/how-can-i-combine-two-fields-in-a-selectlist-text-description\">THIS发布我通过拼凑下面一起的ViewData ：

I am attempting to display 2 fields from my INV_Locations Model within a SelectList: location_dept|location_room or for example IT|Storage. Using THIS post I pieced the below together via ViewData:

INV_AssetsController - 编辑（）获取

    public async Task<ActionResult> Edit(int id)
    {
        if (id == null)
        {
            return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
        }
        INV_Assets iNV_Assets = await db.INV_Assets.FindAsync(id);
        if (iNV_Assets == null)
        {
            return HttpNotFound();
        }

        ViewBag.History = GetHistoryByAssetId(id);

        ViewData["Location_Id"] = new SelectList((from l in db.INV_Locations.ToList() select new { location_room = l.location_dept + "|" + l.location_room }), "location_room", null, null);
    }

INV_AssetsController - 编辑（）HttpPost

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<ActionResult> Edit([Bind(Include = "Id,Model_Id,Manufacturer_Id,Type_Id,Location_Id,Vendor_Id,Status_Id,ip_address,mac_address,note,owner,cost,po_number,description,invoice_number,serial_number,asset_tag_number,acquired_date,disposed_date,created_date,created_by,modified_date,modified_by")] INV_Assets iNV_Assets)
    {
        if (ModelState.IsValid)
        {
            iNV_Assets.modified_date = DateTime.Now;
            iNV_Assets.modified_by = System.Environment.UserName;
            db.Entry(iNV_Assets).State = EntityState.Modified;
            await db.SaveChangesAsync();
            return RedirectToAction("Index", "Home");
        }
        ViewData["Location_List"] = new SelectList((from l in db.INV_Locations.ToList() select new { location_room = l.location_dept + "|" + l.location_room }), "location_room", null, null);
        return View(iNV_Assets);
    }

INV_Assets - 编辑（）查看

        <span class="control-label col-md-2">Location:</span>
        <div class="col-md-4">
            @*@Html.DropDownList("Location_Id", null, htmlAttributes: new { @class = "form-control dropdown" })*@
            @Html.DropDownListFor(model => model.Location_Id, (SelectList)ViewData["Location_List"], htmlAttributes: new { @class = "form-control dropdown", @id = "selectLocation" })
            @Html.ValidationMessageFor(model => model.Location_Id, "", new { @class = "text-danger" })
        </div>

这是接近，渲染（前）在我的下拉列表如下：

This is close, rendering (ex.) the following in my dropdown:

{location_room = IT |服务器} ， {location_room = IT |存储} 等

有谁知道语法变化我需要以仅在选择列表的显示相关的部分（ IT |服务器）？

Does anyone know the syntax change I need to make in order to only display the relevant part in the selectlist (IT|Server)?

推荐答案

您还没有指定在的SelectList dataTextField 属性$ C>构造函数，因此它默认为的ToString（）匿名对象的方法。它需要：（请注意，不需要在最后一个参数）

You have not specified the dataTextField property in the SelectList constructor so it defaults to the ToString() method of the anonymous object. It needs to be: (note the last parameter is not required)

ViewData["Location_List"] = new SelectList((from l in db.INV_Locations.ToList()
  select new { location_room = l.location_dept + "|" + l.location_room }),
  "location_room", "location_room");

旁注：

1. 您的GET方法具有计算机[LOCATION_ID] （我想这是一个
   错字，它应该是计算机[Location_List] （按照POST
   法）


2. 您还没有表现出你的模型，但 LOCATION_ID 建议的
   标识属性（通常为 INT ），所以我不知道你会怎样
   预计这个工作。您具有约束力的文本值IT |服务器或
   IT |存储的财产 LOCATION_ID 我怀疑没有
   关系模型或数据库中的字段。我怀疑什么
   你真的需要这里级联下拉列表，一个用于
   部门，第二个供房（绑定到 LOCATION_ID
   这是利用最新的AJAX当选择一个部门。


3. 我建议你重新系数生成的的SelectList （和其他
   普通code）到一个私有方法，以避免重复code。


4. 我强烈建议你学会使用视图模型，并停止混淆
   模型 ViewBag 和的ViewData ，然后取出那个可怕
[绑定（包括=..）] 属性



1. Your GET method has ViewData["Location_Id"] (I assume this is a typo and it should be ViewData["Location_List"] (as per the POST method)
2. You have not shown your model but Location_Id would suggest an identifier property (usually int) so I am not sure how you would expect this to work. You are binding the text value "IT|Server" or "IT|Storage" to the property Location_Id which I suspect has no relationship to your model or the database fields. I suspect what you really need here is cascading dropdown lists, one for the department, and the second for the room (bound to Location_Id which is updated using ajax when a department is selected.
3. I suggest you re-factor generating the SelectList (and other common code) to a private method to avoid duplicating code.
4. I strongly recommend you learn to use view models and stop mixing up models ViewBag and ViewData and remove that dreadful [Bind(Include = "..")] attribute

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