DropDownListFor不选择价值 [英] DropDownListFor Not Selecting Value

问题描述

我使用的是编辑页面内的DropDownListFor辅助方法，而我没有任何运气得到它的选择，我指定的值。我注意到一个<一个href=\"http://stackoverflow.com/questions/1916462/dropdownlistfor-in-editortemplate-not-selecting-value\">similar问题的＃2。建议的解决方法是，填充在视图code你的SelectList。问题是，我已经尝试这样做，它仍然没有工作。

I'm using the DropDownListFor helper method inside of an edit page and I'm not having any luck getting it to select the value that I specify. I noticed a similar question on Stackoverflow. The suggested workaround was to, "populate your SelectList in the view code". The problem is that I've already tried this and it's still not working.

<%= Html.DropDownListFor(model => model.States, new SelectList(Model.States.OrderBy(s => s.StateAbbr), "StateAbbr", "StateName", Model.AddressStateAbbr), "-- Select State --")%>

我设置一个断点，并已验证model.AddressStateAbbr的存在（和有效性）。我只是不知道我错过了什么。

I have set a breakpoint and have verified the existence (and validity) of model.AddressStateAbbr. I'm just not sure what I'm missing.

推荐答案

研究了一个小时后，我发现选择不会被设置为 DropDownListFor 。原因是你正在使用ViewBag的名字一样的模型的属性。

After researching for an hour, I found the problem that is causing the selected to not get set to DropDownListFor. The reason is you are using ViewBag's name the same as the model's property.

示例

public  class employee_insignia
{ 
   public int id{get;set;}
   public string name{get;set;}
   public int insignia{get;set;}//This property will store insignia id
}

// If your ViewBag's name same as your property name 
  ViewBag.Insignia = new SelectList(db.MtInsignia.AsEnumerable(), "id", "description", 1);

查看

 @Html.DropDownListFor(model => model.insignia, (SelectList)ViewBag.Insignia, "Please select value")

选择的选项将不设置为DropDownList，但是当你改变ViewBag的名字，以不同的名称选择的选项将显示正确的。

The selected option will not set to dropdownlist, BUT When you change ViewBag's name to different name the selected option will show correct.

示例

ViewBag.InsigniaList = new SelectList(db.MtInsignia.AsEnumerable(), "id", "description", 1);

查看

 @Html.DropDownListFor(model => model.insignia, (SelectList)ViewBag.InsigniaList , "Please select value")

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