具有空选择的SelectList [英] SelectList with a null selection

问题描述

我的视图中有很多下拉列表，例如：

I have a bunch of drop down lists in my view, such as this one:

@Html.DropDownListFor(model => model.Process, Model.ProcessList)

它们都包含 SelectList 基于这样的数据库表数据：

They all take in a SelectList based on data from a database table like this:

ProcessList = new SelectList(_db.Processes, "ID", "Name");

其中 _db.Processes 返回 ObjectSet< Process> 。

我遇到的问题是，有时下拉列表设置的属性可能是没有选择，即 null 。如何将 null 选择添加到 SelectList >

The issue I have is that sometimes the property that is set by the drop down list can be no selection, i.e. null. How can I add a null selection to the SelectList>

推荐答案

@Html.DropDownListFor(model => model.Process, Model.ProcessList,"--Select Process--")

以上行将添加-选择过程-在选择列表的顶部，如果选择了此值，则将发布空字符串，并将bound属性设置为null（在这种情况下为Process）

The above line would add --select process-- at the top of select list and if this value is selected, empty string will be posted and bound property will be set to null (Process in this case)

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