验证下拉列表的第一项是“选择" [英] Validation For Dropdownlist whose first item is 'select'

问题描述

我已经在设计部分完成了此操作

I have done this one in the design section

<asp:DropDownList ID="ddlSubject" runat="server" AutoPostBack="true">
            </asp:DropDownList>
            <asp:RequiredFieldValidator  ID="RequiredFieldValidator7" runat="server" ControlToValidate="ddlSubject" ValidationGroup="course"  InitialValue="0" ErrorMessage="Please Select Subject">*</asp:RequiredFieldValidator>

选择受代码背后的约束

Select is bound by code behind

ddlSubject.DataSource = objQuiz.SelectAllSubject
            ddlSubject.DataTextField = "SubjectName"
            ddlSubject.DataValueField = "SubjectId"
            ddlSubject.DataBind()
            Dim l As New ListItem("-------------Select--------------------", "-1")
            l.Selected = True
            ddlSubject.Items.Add(l)

请解决这个
谢谢

please solve this
thank you

推荐答案

只需执行以下操作:

将-1" 替换为"0" ，因为提到您 InitialValue ="0"

您的代码是

Hi,
Just do the following:

Replace "-1" with "0" because you are mentioned InitialValue="0"

Your code is

Dim l As New ListItem("-------------Select--------------------", "0")

谢谢，
Imdadhusen

Thanks,
Imdadhusen

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