必填字段验证器不适用于有限的下拉列表 [英] Required Field Validator Is Not Working For Bounded Dropdownlist

问题描述

如何在与数据库绑定的下拉列表上应用验证

how to apply validation on dropdown list which is bounded with database

推荐答案

<asp:DropDownList ID="ddlSuggArea" runat="server" DataSourceID="sdsSuggArea" DataTextField="Area_Desc"



DataValueField="Area_Id" AppendDataBoundItems="True" CausesValidation="True">

<asp:ListItem Selected="True" Value="0">Choose Area...</asp:ListItem>

</asp:DropDownList>

<asp:RequiredFieldValidator ID="rfvSuggArea" runat="server" ErrorMessage="RequiredFieldValidator" ControlToValidate="ddlSuggArea" SetFocusOnError="True" InitialValue="0">Please choose a topic area</asp:RequiredFieldValidator>

添加所需的字段验证器为:

add required field validator as:

<asp:RequiredFieldValidator

    ID="your_id"

    runat="server"

    ErrorMessage="Please Select Value"

    ControlToValidate="your_dropdownlist"

    InitialValue="-Select-"

    Display="dynamic"

    Enabled="false">
</asp:RequiredFieldValidator>

将数据源绑定到下拉列表后，将第一个选项插入为请选择".
在必填字段验证器中设置Intial值.

可以在下拉菜单中添加新值，如下所示:

Once you bind the datasource to the Dropdownlist, insert first option as "Please Select".
Set the Intial value in Required field validator.

New value can be added in dropdown as follows:

your_dropdownlist.Items.Insert(0, new ListItem("-Select-","-Select-");

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