You need to set the .model-open as below.
.modal-open
{
overflow: scroll;
}
Refer the below article for your reference and implement it as per your code logic.
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title></title>
<meta name="viewport" content="width=device-width, initial-scale=1" />
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" />
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.2.1/jquery.min.js"></script>
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link href='https://fonts.googleapis.com/css?family=Open+Sans:400,300,300italic,400italic,600'
rel='stylesheet' type='text/css' />
<link href="https://fonts.googleapis.com/css?family=Montserrat" rel="stylesheet"
type="text/css" />
<script src="//code.jquery.com/ui/1.12.1/jquery-ui.js"></script>
<link rel="stylesheet" href="//code.jquery.com/ui/1.12.1/themes/smoothness/jquery-ui.css">
<style>
.modal-header, h4, .close
{
background-color: #5cb85c;
color: white !important;
text-align: center;
font-size: 30px;
}
.modal-footer
{
background-color: #f9f9f9;
}
.modal-open
{
overflow: scroll;
}
</style>
<script type="text/javascript">
function ShowPopup_card() {
$("#btnShowPopup").click();
$("#myModal").draggable();
}
</script>
</head>
<body>
<form id="form1" runat="server">
<asp:LinkButton ID="Nav_Lb_Add" runat="server" OnClick="Nav_Lb_Add_Click">Add CardRecord</asp:LinkButton>
<br />
1. This is a sample text
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<asp:Panel ID="Panel1" runat="server">
<div id="myModal" class="modal fade">
<div class="modal-dialog">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-label="Close">
<span aria-hidden="true">×</span></button>
<h4 class="modal-title">
Card Selection</h4>
</div>
<div class="modal-body" style="text-align: center">
<asp:Label ID="lblMessage" runat="server" />
<asp:Panel ID="PL_CardSelect" runat="server">
<asp:DropDownList ID="ddl_CardSelection" runat="server">
<asp:ListItem>SELECT Card</asp:ListItem>
<asp:ListItem>Sequential</asp:ListItem>
<asp:ListItem>Random</asp:ListItem>
</asp:DropDownList>
<br />
<asp:Label runat="server" ID="lblmsgcard"></asp:Label>
</asp:Panel>
</div>
<div class="modal-footer">
<asp:Button runat="server" ID="Button1" class="btn btn-default" Text="Close" UseSubmitBehavior="false">
</asp:Button>
<asp:Button runat="server" class="btn btn-primary" ID="Btn_CardSelection" Text="Submit"
UseSubmitBehavior="false" />
</div>
</div>
<!-- /.modal-content -->
</div>
<!-- /.modal-dialog -->
</div>
</asp:Panel>
<%-- Hidden Button for Card Selection --%>
<button type="button" style="display: none;" id="btnShowPopup" class="btn btn-primary btn-lg"
data-toggle="modal" data-target="#myModal">
Launch demo modal</button>
<!-- /.modal -->
</form>
</body>
</html>
C#
protected void Nav_Lb_Add_Click(object sender, EventArgs e)
{
ClientScript.RegisterStartupScript(this.GetType(), "alert", "ShowPopup_card();", true);
this.lblMessage.Text = "Please select the Card to Add Record";
ddl_CardSelection.SelectedValue = "SELECT Card";
lblmsgcard.Visible = false;
}
VB.Net
Protected Sub Nav_Lb_Add_Click(sender As Object, e As EventArgs)
ClientScript.RegisterStartupScript(Me.[GetType](), "alert", "ShowPopup_card();", True)
Me.lblMessage.Text = "Please select the Card to Add Record"
ddl_CardSelection.SelectedValue = "SELECT Card"
lblmsgcard.Visible = False
End Sub
Screenshot
