Dropdown Required field validator

Question

I have one drop down and it fills the value automatically from database. For that I'm using the following code in the front-end:

public void des_fill()
{
     string q = "SELECT -1 AS pick_det_id,'' AS pick_det_name UNION select pick_det_id,pick_det_name from tbl_pick_list_detail where pick_hdr_id=(select pick_hdr_id from tbl_pick_list_header where pick_hdr_name='Designation')";
     isopen();
     conn.Open();
     code cd = new code();
     SqlDataReader dr = cd.Reader(q);
     ddlDes.DataSource = dr;
     ddlDes.DataValueField = "pick_det_id";
     ddlDes.DataTextField = "pick_det_name";
     ddlDes.DataBind();
     conn.Close();
}

I am using this:

SELECT -1 AS pick_det_id,'' AS pick_det_name UNION

for the starting dropdown value as empty.

But by using this required field is not working. When I click the Save button it doesn't asks for required field, and saves the record.

Answer 1

@thiru for required field validator place InitialValue=0 <asp:RequiredFieldValidator ID="RFVQualification" runat="server" ControlToValidate="ddlQualification" CssClass="requiredfieldvalidatorstyle" Display="Static" ErrorMessage="*" InitialValue="0"></asp:RequiredFieldValidator>

here InitalValue refers to the the starting Index of the DropDown

Answer 2

do the following, add text box with ValidationGroup and validate that group on c# level as the following:

for Textbox

<asp:TextBox ID="FirstName" runat="server" 
        AutoPostBack="false" ValidationGroup="UserInfor"></asp:TextBox>

<asp:RequiredFieldValidator ID="RequiredFieldValidator1"
     runat="server" ControlToValidate="FirstName"    
     ErrorMessage="First Name is requried" ForeColor="Red"
     ValidationGroup="UserInfor">    </asp:RequiredFieldValidator>

for dropdownlist, you should add value InitialValue as the following:

<asp:DropDownList runat="server" id="ddAge"  ValidationGroup="UserInfor">
<asp:ListItem Value="-1" text="Select a Value">
<asp:ListItem Value="15" text="15 years">
<asp:ListItem Value="20" text="20 years">
<asp:ListItem Value="30" text="30 years">
</asp:DropDownList>


<asp:RequiredFieldValidator ID="RequiredFieldValidator2"
     runat="server" ControlToValidate="ddAge"   InitialValue="-1"  
     ErrorMessage="Age requried" ForeColor="Red"
     ValidationGroup="UserInfor">    </asp:RequiredFieldValidator>

then in the c# level, add the following:

Validate("UserInfor");
    if (Page.IsValid) {
                lblOutput.Text = "Required field is filled!";
             }
             else {
                lblOutput.Text = "Required field is empty!";
             }