asp.net下拉列表findbytext [英] asp.net dropdown list findbytext

问题描述

我正在使用以下内容选择下拉列表，从列表中选择一个项目:

I am using the following to select have the dropdown list select an item from the list:

    ddlIndustry.Items.FindByText("Trucking").Selected = true;

是否有另一种逻辑可以做到这一点.

Is there another logic for doing this.

我注意到我是否这样做:

I noticed if I do:

   ddlIndustry.Items.FindByText("Trucking").Selected = true;

然后在代码中执行以下操作:

and then down the code do something like:

   ddlIndustry.Items.FindByText("Cards").Selected = true; 

我收到一条错误消息，说无法选择多个项目.

I get an error saying cannot select multiple items.

推荐答案

这是您要执行的操作:

ddlIndustry.SelectedValue = ddlIndustry.Items.FindByText("Cards").Value;

问题在于将 ListItem 设置为 Selected 不会清除对其他ListItem的选择.请记住， Items 属性是一个 ListItemColletion ，它也用在 ListBox 和 CheckListBox 中，它们允许多个项目选择(而 DropDownList 不允许这样做，这就是您收到错误的原因).

The problem is that making ListItem as Selected does not clear selection of other ListItems. Keep in mind that Items property is a ListItemColletion, which is also used in ListBox and CheckListBox, which allow multiple item selection (while DropDownList does not allow that, which is why you got the error).

使用 DropDownList 的 SelectedValue 属性可以为您进行多项选择，取消选择以前选择的项目，然后按值选择新项目.

Using the SelectedValue propery of the DropDownList takes care of the multi-selection for you, unselecting previously selected items and selecting the new item by value.

您可以在此处检查相关问题: https://stackoverflow.com/a/16068632/570191

You can check for a correlated issue here: https://stackoverflow.com/a/16068632/570191

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