Hi Monique,
Use the CSS height and overflow-y and Also add maxHeight property.
Here is the working sample code. You can also download the zip file of sample.
HTML
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.7.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap/5.1.3/css/bootstrap.min.css" media="screen" />
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap/5.1.3/js/bootstrap.bundle.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.13/css/bootstrap-multiselect.css">
<script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-multiselect/0.9.13/js/bootstrap-multiselect.js"></script>
<script type="text/javascript">
$(function () {
$('[id*=lstFruits]').multiselect({
includeSelectAllOption: true,
maxHeight: 450,
templates: {
button: '<button type="button" class="multiselect dropdown-toggle" data-bs-toggle="dropdown"><span class="multiselect-selected-text"></span></button>'
}
});
});
</script>
<style type="text/css">
ul { height: 100px; width: 175px; overflow-y: scroll; }
</style>
</head>
<body class="container">
<form id="form1" runat="server">
<asp:ListBox ID="lstFruits" runat="server" SelectionMode="Multiple">
<asp:ListItem Text="Mango" Value="1" />
<asp:ListItem Text="Apple" Value="2" />
<asp:ListItem Text="Banana" Value="3" />
<asp:ListItem Text="Guava" Value="4" />
<asp:ListItem Text="Orange" Value="5" />
</asp:ListBox>
<asp:Button Text="Submit" runat="server" OnClick="Submit" />
</form>
</body>
</html>
Namespace
C#
using System.Web.UI.WebControls;
VB.Net
Imports System.Web.UI.WebControls
C#
protected void Submit(object sender, EventArgs e)
{
string message = "";
foreach (ListItem item in lstFruits.Items)
{
if (item.Selected)
{
message += item.Text + " " + item.Value + "\\n";
}
}
ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('" + message + "');", true);
}
VB.Net
Protected Sub Submit(sender As Object, e As EventArgs)
Dim message As String = ""
For Each item As ListItem In lstFruits.Items
If item.Selected Then
message += item.Text + " " + item.Value + "\n"
End If
Next
ClientScript.RegisterStartupScript(Me.GetType(), "alert", "alert('" & message & "');", True)
End Sub
Screenshot
