Using 24 Hour TimePicker control in ASP.Net

Hi muhammad12,

Refer article => Bootstrap TimePicker in ASP.Net with C# and VB.Net

I have modified it based on your requirement.

1. For preventing user from manually enter the time, I have used onkeydown JavaScript event handler.

<asp:TextBox ID="txtTime" runat="server" CssClass="form-control" onkeydown="return false;" />

2. For 24 hours format, I have set the property.

<script type="text/javascript">
    $(function () {
        $('[id*=txtTime]').datetimepicker({
            //24 Hours Format
            format: 'HH:mm'
        });
    });
</script>