空值添加到ASP.net MVC一个DropDownList [英] Add empty value to a DropDownList in ASP.net MVC

问题描述

我建立一个数据输入接口，并已成功地结合具有用于使用的DropDownList所以用户从$ P $对配置的值选择其数据参考表中的列

I'm building a data entry interface and have successfully bound the columns that have reference tables for their data using DropDownList so the user selects from the pre-configured values.

我现在的问题是，我不希望被默认选中的第一个值千万，我需要强制用户从列表中选择一个值，以避免错误，他们没有接那场，默认情况下一个价值分配。

My problem now is that I don't want the first value to be selected by default, I need to force the user to select a value from the list to avoid errors where they didn't pick that field and by default a value was assigned.

是否有这样做的更优雅的方式，而不是增加code，包括在列表顶部的空值后，我从数据库中得到它之前，我在我的控制器类把它传递给选择列表的构造？

Is there a more elegant way of doing this than to add code to include an empty value at the top of the list after I get it from the database and before i pass it to the SelectList constructor in my controller class?

推荐答案

在HTML辅助函数有一个'第一个空值参数作为第三个参数。

The Html helper function takes a 'first empty value' parameter as the third argument.

<%=Html.DropDownList("name",dataSource,"-please select item-")%>

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