如何添加一个RequiredFieldValidator到DropDownList控件？ [英] How to add a RequiredFieldValidator to DropDownList control?

问题描述

我把的DropDownList 我绑定使用的SqlDataSource 控制从数据库中显示的值。

I took the DropDownList and I binded the control using SqlDataSource to display the values from the database.

当我使用的RequiredFieldValidator 验证我无法使它工作。

When I am validating using RequiredFieldValidator I am unable to make it work.

推荐答案

有关你对待它，如果你是验证任何其他类型的控制，但使用必填字段校验器的与InitialValue财产的大部分。

For the most part you treat it as if you are validating any other kind of control but use the InitialValue property of the required field validator.

<asp:RequiredFieldValidator ID="rfv1" runat="server" ControlToValidate="your-dropdownlist" InitialValue="Please select" ErrorMessage="Please select something" />

基本上就是它说的是，如果在DropDownList选择比与InitialValue的1套其他任何值验证会成功。

Basically what it's saying is that validation will succeed if any other value than the 1 set in InitialValue is selected in the dropdownlist.

如果您数据绑定需要事后插入请选择值如下：

If databinding you will need to insert the "Please select" value afterwards as follows

this.ddl1.Items.Insert(0, "Please select");

这篇关于如何添加一个RequiredFieldValidator到DropDownList控件？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！