Hi Guys I'm New to web development.
i need one help. I'm having list box on my form, in form load event i will bind the list box with database value. user should be able to select only 5 items from the list box and also i want to validate onsubmit button click weather user is selected 5 items or not . if not give alert. client side java-script i need to use? sample code will help.
Tanks.
You can do so by adding AJAX - updatepanel. Map the button's click with trigger of updatepanel where you can get the count of selected items.
Hi Guys I'm New to web development.
i need one help. I'm having list box on my form, in form load event i will bind the list box with database value. user should be able to select only 5 items from the list box and also i want to validate onsubmit button click weather user is selected 5 items or not . if not give alert. client side java-script i need to use? sample code will help.
Tanks.
Hi,
I am not sure if this will help but here is a form Validate code to check if all field have entries.
<script language="JavaScript"><!--
function Form_Validator(theForm){
if (theForm.Name.value=="")
{
alert("Please enter your Name.")
theForm.Name.focus()
return false
}
if (theForm.Address.value==""){
alert("Please enter your Address.")
theForm.Address.focus()
return false
}
if (theForm.PostCode.value==""){
alert("Please enter your Post Code.")
theForm. PostCode.focus()
return false
}
if (theForm.Email.value==""){
alert("Please enter your E-Mail Address.")
theForm.Email.focus()
return false
}
if (theForm.Message.value==""){
alert("Please enter your Message.")
theForm.Message.focus()
return false
}
}
-->
</script>Above Code Called from Form onSubmit
<form method="POST" action="YourPage.asp" onSubmit="return Form_Validator(this)" name="theForm"> Rest of your Form </Form>Hope this helps
Doreenpen
Thanks for ur reply.
i think the above code will not help.
i need to prevent user from not selecting more than 5 items.
Try this.
<head runat="server">
<script type="text/javascript">
function ValidateForm() {
var t = document.getElementById("lst1");
var count = 0;
for (i = 0; i < t.length; i++) {
if (t.item(i).selected)
count++;
}
if (count < 5)
return false;
return true;
}
</script>
</head>
<body>
<form id="form1" runat="server" onsubmit="return ValidateForm()">
<div>
<asp:ListBox SelectionMode="Multiple" ID="lst1" runat="server" Height="95px" Width="86px">
<asp:ListItem Value="1" Text="Test1"/>
<asp:ListItem Value="2" Text="Test2"/>
<asp:ListItem Value="3" Text="Test3"/>
<asp:ListItem Value="4" Text="Test4"/>
<asp:ListItem Value="5" Text="Test5"/>
<asp:ListItem Value="6" Text="Test6"/>
<asp:ListItem Value="7" Text="Test7"/>
<asp:ListItem Value="8" Text="Test8"/>
<asp:ListItem Value="9" Text="Test9"/>
</asp:ListBox>
<asp:Button ID="btn1" runat="server" Text="Submit" />
</div>
</form>
</body>Hi thanks for you reply.
i found the solution for that. here is the code.
<asp:ListBox ID="lstbox" runat="server" SelectionMode="Multiple"
AutoPostBack="true" CausesValidation="true" OnSelectedIndexChanged="lstbox_SelectedIndexChanged1" >
<asp:ListItem Text="one" Value="1"></asp:ListItem>
<asp:ListItem Text="two" Value="2"></asp:ListItem>
<asp:ListItem Text="three" Value="3"></asp:ListItem>
<asp:ListItem Text="Four" Value="4"></asp:ListItem>
<asp:ListItem Text="Five" Value="5"></asp:ListItem>
</asp:ListBox>
<asp:CustomValidator ID="CustomValidator1" runat="server" Display="Dynamic" ErrorMessage="Please select 3 items only."
OnServerValidate="CustomValidator1_ServerValidate" >
</asp:CustomValidator>Code behind:
protected void CustomValidator1_ServerValidate(object sender, ServerValidateEventArgs args)
{
int count = 0;
for (int i = 0; i < lstbox.Items.Count; i++)
{
if (lstbox.Items[i].Selected)
count++;
}
if (count <= 2)
{
args.IsValid = true;
}
else
args.IsValid = false;
}
protected void lstbox_SelectedIndexChanged1(object sender, EventArgs e)
{
int count = 0;
int i = 0;
System.Web.UI.WebControls.ListBox sen = default(System.Web.UI.WebControls.ListBox);
sen = (System.Web.UI.WebControls.ListBox)sender;
for (i = 0; i <= lstbox.Items.Count - 1; i++)
{
if (lstbox.Items[i].Selected == true)
{
count = count + 1;
}
}
if (count > 3)
{
lstbox.Items[sen.SelectedIndex].Selected = false;
}
}We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.