Add ASP.Net DropDownList inside Bootstrap Modal Popup

Hi makumnbi,

You need to add ASP:DropDownList instead of TextBox.

HTML

<asp:Panel ID="Panel1" runat="server" Style="background-color: #FFFFFF" Height="600px" BorderColor="#6699FF" BorderStyle="Double" Font-Size="Medium">
    <table class="auto-style1">
        <tr>
            <td class="auto-style32" style="background-color: #FFFFFF">
                <asp:GridView ID="SearchGrid" runat="server" AutoGenerateColumns="False" ItemStyle-Width="Auto" PageSize="25"
                    ShowFooter="True" ShowHeaderWhenEmpty="True" Width="877px" Height="274px">
                    <Columns>
                        <asp:TemplateField HeaderText="Account">
                            <EditItemTemplate>
                                <asp:TextBox ID="TextBox6" runat="server" Text='<%# Bind("ADMNO") %>'></asp:TextBox>
                            </EditItemTemplate>
                            <ItemTemplate>
                                <asp:Label ID="account0" runat="server" Text='<%# Bind("ADMNO") %>'></asp:Label>
                            </ItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Student Name">
                            <EditItemTemplate>
                                <asp:TextBox ID="Names" runat="server"></asp:TextBox>
                            </EditItemTemplate>
                            <FooterTemplate>
                                <asp:TextBox ID="Namesf" runat="server" Text='<%# Eval("Name") %>' Width="335px"></asp:TextBox>
                            </FooterTemplate>
                            <ItemTemplate>
                                <asp:Label ID="Name" runat="server" Text='<%# Eval("Name") %>'></asp:Label>
                            </ItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Class">
                            <EditItemTemplate>
                                <asp:TextBox ID="TextBox2" runat="server" Text='<%# Bind("Class") %>'></asp:TextBox>
                            </EditItemTemplate>
                            <FooterTemplate>
                                <asp:DropDownList ID="Classtf" runat="server">
                                </asp:DropDownList>
                            </FooterTemplate>
                            <ItemTemplate>
                                <asp:Label ID="Class" runat="server" Text='<%# Bind("Class") %>'></asp:Label>
                            </ItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Stream">
                            <EditItemTemplate>
                                <asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("Stream") %>'></asp:TextBox>
                            </EditItemTemplate>
                            <FooterTemplate>
                                <asp:DropDownList ID="Streamdf" runat="server">
                                </asp:DropDownList>
                            </FooterTemplate>
                            <ItemTemplate>
                                <asp:Label ID="Stream" runat="server" Text='<%# Bind("Stream") %>'></asp:Label>
                            </ItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Sex">
                            <EditItemTemplate>
                                <asp:TextBox ID="TextBox4" runat="server" Text='<%# Bind("Sex") %>'></asp:TextBox>
                            </EditItemTemplate>
                            <FooterTemplate>
                                <asp:DropDownList ID="Sexdf" runat="server">
                                </asp:DropDownList>
                            </FooterTemplate>
                            <ItemTemplate>
                                <asp:Label ID="colour" runat="server" Text='<%# Bind("Sex") %>'></asp:Label>
                            </ItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Status">
                            <EditItemTemplate>
                                <asp:TextBox ID="TextBox5" runat="server" Text='<%# Bind("Status") %>'></asp:TextBox>
                            </EditItemTemplate>
                            <ItemTemplate>
                                <asp:Label ID="Status0" runat="server" Text='<%# Bind("Status") %>'></asp:Label>
                            </ItemTemplate>
                        </asp:TemplateField>
                        <asp:TemplateField HeaderText="Sudent Type" SortExpression="studenttype">
                            <EditItemTemplate>
                                <asp:TextBox ID="TextBox7" runat="server" Text='<%# Bind("studenttype") %>'></asp:TextBox>
                            </EditItemTemplate>
                            <FooterTemplate>
                                <asp:DropDownList ID="SudentType0" runat="server">
                                    <asp:ListItem></asp:ListItem>
                                    <asp:ListItem>BOARDER</asp:ListItem>
                                    <asp:ListItem>DAY</asp:ListItem>
                                </asp:DropDownList>
                            </FooterTemplate>
                            <ItemTemplate>
                                <asp:Label ID="Label1" runat="server" Text='<%# Bind("studenttype") %>'></asp:Label>
                            </ItemTemplate>
                        </asp:TemplateField>
                        <asp:ButtonField CommandName="Staff" HeaderText="Select" Text="Select" />
                    </Columns>
                </asp:GridView>
            </td>
        </tr>
    </table>
    <div class="Pager"></div>
    <div id="myModal" class="modal fade" style="width: auto;">
        <div class="modal-dialog">
            <div class="modal-content">
                <div class="modal-header">
                    <button style="padding: 0px" type="button" data-dismiss="modal">&times;</button>
                    <h4>Customers's Details</h4>
                </div>
                <div class="modal-body">
                    <div>
                        <div class="form-group">
                            <asp:Label ID="lblId" runat="server"></asp:Label>
                        </div>
                        <div class="form-group">
                            <asp:TextBox ID="txtName" runat="server"></asp:TextBox>
                        </div>
                        <div class="form-group">
                            <asp:TextBox ID="txtCity" runat="server"></asp:TextBox>
                        </div>
                        <div class="form-group">
                            <asp:DropDownList ID="ddlCountries" DataTextField="Country" DataValueField="Country" runat="server">
                                <asp:ListItem Text="Please select" ></asp:ListItem>
                                <asp:ListItem Text="India"></asp:ListItem>
                                <asp:ListItem Text="United States"></asp:ListItem>
                            </asp:DropDownList>
                        </div>
                    </div>
                </div>
                <div class="modal-footer">
                    <button type="button" class="btn btn-info" data-dismiss="modal">
                        Close</button>
                    <asp:Button ID="btnSubmit" runat="server" Text="Submit" CssClass="btn btn-success" />
                </div>
            </div>
        </div>
    </div>
</asp:Panel>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/css/bootstrap.min.css" />
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script type="text/javascript" src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.2/js/bootstrap.min.js"></script>
<script src="ASPSnippets_Pager.min.js"></script>
<script type="text/javascript">
    $(function () {
        GetCustomers(1);
    });
    $("[id*=txtSearch]").live("keyup", function () {
        GetCustomers(parseInt(1));
    });
    $(".Pager .page").live("click", function () {
        GetCustomers(parseInt($(this).attr('page')));
    });

    function SearchTerm() {
        return jQuery.trim($("[id*=txtSearch]").val());
    };
    function GetCustomers(pageIndex) {
        $.ajax({
            type: "POST",
            url: "CS.aspx/GetCustomers",
            data: '{searchTerm: "' + SearchTerm() + '", pageIndex: ' + pageIndex + '}',
            contentType: "application/json; charset=utf-8",
            dataType: "json",
            success: OnSuccess,
            failure: function (response) {
                alert(response.d);
            },
            error: function (response) {
                alert(response.d);
            }
        });
    }
    var row;
    function OnSuccess(response) {
        var xmlDoc = $.parseXML(response.d);
        var xml = $(xmlDoc);
        var customers = xml.find("Customers");
        if (row == null) {
            row = $("[id*=SearchGrid] tr:last-child").clone(true);
        }
        var footer = $("[id*=SearchGrid] tr:last-child").clone(true);
        $("[id*=SearchGrid] tr").not($("[id*=SearchGrid] tr:first-child")).remove();
        if (customers.length > 0) {
            $.each(customers, function () {
                var customer = $(this);
                $("td", row).eq(0).html($(this).find("CustomerID").text());
                $("td", row).eq(1).html($(this).find("ContactName").text());
                $("td", row).eq(2).html($(this).find("City").text());
                $("td", row).eq(3).html($(this).find("Country").text());
                $("td", row).eq(4).html($(this).find("Address").text());
                $("td", row).eq(5).html($(this).find("Phone").text());
                $("td", row).eq(6).html($(this).find("PostalCode").text());
                $("td", row).eq(7).html("<a href='javascript:;' onclick='GetData(this)'>Select</a>");
                $("[id*=SearchGrid]").append(row);
                row = $("[id*=SearchGrid] tr:last-child").clone(true);
            });
            $("[id*=SearchGrid]").append(footer);
            var pager = xml.find("Pager");
            $(".Pager").ASPSnippets_Pager({
                ActiveCssClass: "current",
                PagerCssClass: "pager",
                PageIndex: parseInt(pager.find("PageIndex").text()),
                PageSize: parseInt(pager.find("PageSize").text()),
                RecordCount: parseInt(pager.find("RecordCount").text())
            });

            $(".Name").each(function () {
                var searchPattern = new RegExp('(' + SearchTerm() + ')', 'ig');
                $(this).html($(this).text().replace(searchPattern, "<span class = 'highlight'>" + SearchTerm() + "</span>"));
            });
        } else {
            var empty_row = row.clone(true);
            $("td:first-child", empty_row).attr("colspan", $("td", row).length);
            $("td:first-child", empty_row).attr("align", "center");
            $("td:first-child", empty_row).html("No records found for the search criteria.");
            $("td", empty_row).not($("td:first-child", empty_row)).remove();
            $("[id*=SearchGrid]").append(empty_row);
        }
    };
    function GetData(ele) {
        var row = $(ele).closest('tr');
        var id = $("td", row).eq(0).html();
        var name = $("td", row).eq(1).html();
        var city = $("td", row).eq(2).html();
        var country = $("td", row).eq(3).html();

        $('[id*=lblId]').html(id);
        $('[id*=txtName]').val(name);
        $('[id*=txtCity]').val(city);
        $('[id*=ddlcountries]').val(city);
                
        $('[id*=myModal]').modal('show');
    }
</script>

Namespaces

using System.Data;
using System.Data.SqlClient;
using System.Configuration;

Code

protected void Page_Load(object sender, System.EventArgs e)
{
    if (!IsPostBack)
    {
        this.BindDummyRow();
    }
}

[System.Web.Services.WebMethod()]
public static string GetCustomers(string searchTerm, int pageIndex)
{
    string query = "[GetCustomersPageWiseSearch]";
    SqlCommand cmd = new SqlCommand(query);
    cmd.CommandType = CommandType.StoredProcedure;
    cmd.Parameters.AddWithValue("@SearchTerm", searchTerm);
    cmd.Parameters.AddWithValue("@PageIndex", pageIndex);
    cmd.Parameters.AddWithValue("@PageSize", 10);

    cmd.Parameters.Add("@RecordCount", SqlDbType.Int, 4).Direction = ParameterDirection.Output;
    return GetData(cmd, pageIndex).GetXml();
}

private static DataSet GetData(SqlCommand cmd, int pageIndex)
{
    string strConnString = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (SqlConnection con = new SqlConnection(strConnString))
    {
        using (SqlDataAdapter sda = new SqlDataAdapter())
        {
            cmd.Connection = con;
            sda.SelectCommand = cmd;
            using (DataSet ds = new DataSet())
            {
                sda.Fill(ds, "Customers");
                DataTable dt = new DataTable("Pager");
                dt.Columns.Add("PageIndex");
                dt.Columns.Add("PageSize");
                dt.Columns.Add("RecordCount");
                dt.Rows.Add();
                dt.Rows[0]["PageIndex"] = pageIndex;
                dt.Rows[0]["PageSize"] = 10;
                dt.Rows[0]["RecordCount"] = cmd.Parameters["@RecordCount"].Value;
                ds.Tables.Add(dt);
                return ds;
            }
        }
    }
}

private void BindDummyRow()
{
    DataTable dummy = new DataTable();
    dummy.Columns.Add("ADMNO");
    dummy.Columns.Add("Name");
    dummy.Columns.Add("Class");
    dummy.Columns.Add("Stream");
    dummy.Columns.Add("Sex");
    dummy.Columns.Add("Status");
    dummy.Columns.Add("studenttype");
    dummy.Rows.Add();
    this.SearchGrid.DataSource = dummy;
    this.SearchGrid.DataBind();
}

Screenshot