Compare Field validator for Drop down list ="--Select--"

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Hello Experts,

I have a dropdownlist which datasource is filled from DB and with an initial value as "--Select--","0"
If I don't select dropdown it shows "--Select--" and assumes that is entered and so it doesn't ask to enter required field.

Here is my asp.net code

XML

<asp:DropDownList ID="ddlDState" runat="server" Width="100%" AutoPostBack="true">
                       </asp:DropDownList>
                         <asp:RequiredFieldValidator ID="RequiredFieldValidator12" runat="server" ControlToValidate="ddlDState" InitialValue="0" ValidationGroup="Required" ErrorMessage="*" ForeColor="Red"/>

Here is my Vb.Net code

VB

Dim ds As New DataSet
        ds = dbnet.FillStates()
        ddlDState.DataSource = ds
        ddlDState.DataValueField = "STATE"
        ddlDState.DataBind()
        ddlDState.Items.Insert(0, New ListItem("--Select--", "0"))

Now my problem is I want to show if ddl is not selected and is still having "--Select--" it should say "Please enter fields required"

It may be something silly I am missing. But I am not sure of it.
Will anything work with Compare Validator ?

Posted 5-Feb-15 4:10am

sudevsu

Updated 5-Feb-15 5:01am

v3

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Comments

ZurdoDev 5-Feb-15 11:07am

I'd suggest just adding a Validat() function in JS and check it there.

sudevsu 5-Feb-15 11:16am

Meaning you want to me to add Js function on dropdown list and check if it is not "--Select--" then go thru.
I don't think u can javascript function on Dropdown list. Correct me if I am wrong

ZurdoDev 5-Feb-15 11:22am

Sure. Javascript can access anything on the page.

And if you use jQuery it's very easy:
$("#myselect").val();

sudevsu 5-Feb-15 11:27am

I am still not clear. You want me add a JSfunction on Button click or ddl change ?

ZurdoDev 5-Feb-15 12:03pm

You can do it however you want. If you want it to happen immediately then put it on the ddl change. If you want to wait until the form is submitted use OnClientClick of the ASP.Net button used to submit the form.

sudevsu 5-Feb-15 13:09pm

<asp:DropDownList ID="ddlDState" runat="server" Width="100%" AutoPostBack="true" OnSelectedIndexChanged="ddlDState_SelectedIndexChanged">

<asp:RequiredFieldValidator ID="RequiredFieldValidator12" runat="server" ControlToValidate="ddlDState" InitialValue="--Select--" ValidationGroup="Required" ErrorMessage="*" ForeColor="Red"/>

Protected Sub ddlDState_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddlDState.SelectedIndexChanged

If ddlDState.SelectedValue = "--Select--" Then
Dim message As String = "alert('Please Select State')"
ScriptManager.RegisterClientScriptBlock(TryCast(sender, Control), Me.GetType(), "alert", message, True)
End If

Your idea didn't work Ryan. Can you look at the code and tell if I am missing anything?

ZurdoDev 5-Feb-15 13:27pm

You're doing it in C#. I suggested doing it in JS.

sudevsu 5-Feb-15 13:33pm

Yeah correct I am doing in VB.
Can you tell how to do in JavaScript?

ZurdoDev 5-Feb-15 13:36pm

I already did. But I would suggest googling for example.

use onchange="return Validate();" on your dropdown and then add a JS file if you don't have one already and put a function named Validate() in it.

something along the lines of:
function Validate()
{
var ddlValue = $("#myDdl").val();
if (ddlValue == "0")
{
alert("Please select ...");
return false;
}
}

and then take AutoPostBack off of your dropdown.

sudevsu 5-Feb-15 13:12pm

I don't want to wait till the form is submitted. I want it happen immediately.

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