Update selected Repeater row on another page using C# in ASP.Net

Hi gpiyush152,

I have created sample code which fullfill your requirement.

HTML

FirstPage.aspx

<form id="form1" runat="server">
<div>
    <asp:HiddenField ID="hfId" runat="server" />
    <asp:Repeater ID="rptCustomers" runat="server">
        <HeaderTemplate>
            <table id="Customers" border="1" cellpadding="0" cellspacing="0">
                <tr>
                    <th>
                        <asp:Label ID="lblId" Text="Id" runat="server" />
                    </th>
                    <th>
                        <asp:Label ID="lblName" Text="Name" runat="server" />
                    </th>
                    <th>
                        <asp:Label ID="lblCountry" Text="Country" runat="server" />
                    </th>
                </tr>
        </HeaderTemplate>
        <ItemTemplate>
            <tr>
                <td>
                    <asp:Label ID="lblId" Text='<%#Eval("CustomerId")%>' runat="server" />
                </td>
                <td>
                    <asp:Label ID="lblName" Text='<%#Eval("Name")%>' runat="server" />
                </td>
                <td>
                    <asp:Label ID="lblCountry" Text='<%#Eval("Country") %>' runat="server" />
                </td>
            </tr>
        </ItemTemplate>
        <FooterTemplate>
            </table>
        </FooterTemplate>
    </asp:Repeater>
    <asp:HiddenField ID="HiddenField1" runat="server" />
    <br />
    <br />
    <asp:Button ID="btnEdit" Text="Edit" OnClick="OnEdit" runat="server" />
</div>
<div>
    <style type="text/css">
        body
        {
            font-family: Arial;
            font-size: 10pt;
        }
        table
        {
            border: 1px solid #ccc;
        }
        table th
        {
            background-color: #F7F7F7;
            color: #333;
            font-weight: bold;
        }
        table th, table td
        {
            padding: 5px;
            border-color: #ccc;
        }
        .selected_row
        {
            background-color: #A1DCF2;
        }
    </style>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
    <script type="text/javascript">
        $(function () {
            $("[id*=Customers] td").click(function () {
                var row = $(this).parent();
                $("[id*=Customers] tr").each(function () {
                    if ($(this)[0] != row[0]) {
                        $("td", this).removeClass("selected_row");
                    }
                });
                $("td", row).each(function () {
                    if (!$(this).hasClass("selected_row")) {
                        $(this).addClass("selected_row");
                    } else {
                        $(this).removeClass("selected_row");
                    }
                });
                $('[id*=hfId]').val($(this).closest('tr').find('[id*=lblId]')[0].innerHTML);
                return false;
            });
        });
    </script>
</div>
</form>

C#

private string constr = ConfigurationManager.ConnectionStrings["Constr"].ToString();
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.GetData();
    }
}

private void GetData()
{
    using (SqlConnection con = new SqlConnection(constr))
    {

        using (SqlCommand cmd = new SqlCommand("SELECT * FROM Customers", con))
        {
            DataTable dt = new DataTable();
            using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
            {
                sda.Fill(dt);
                rptCustomers.DataSource = dt;
                rptCustomers.DataBind();
            }
        }
    }
}

protected void OnEdit(object sender, EventArgs e)
{
    Response.Redirect("Default2.aspx?Id=" + hfId.Value);
}

Default2.aspx

HTML

<form id="form1" runat="server">
<div>
    <table border="0" cellpadding="0" cellspacing="0">
        <tr>
            <td>
                Id:
            </td>
            <td>
                <asp:Label ID="lblId" Text="" runat="server" />
            </td>
        </tr>
        <tr>
            <td>
                Name:
            </td>
            <td>
                <asp:TextBox ID="txtName" runat="server" />
            </td>
        </tr>
        <tr>
            <td>
                Country:
            </td>
            <td>
                <asp:TextBox ID="txtCountry" runat="server" />
            </td>
        </tr>
        <tr>
            <td>
                <asp:Button Text="Update" runat="server" />
            </td>
            <td>
                <asp:Button Text="Cancel" runat="server" />
            </td>
        </tr>
    </table>
</div>
<div>
    <style type="text/css">
        body
        {
            font-family: Arial;
            font-size: 10pt;
        }
        table
        {
            border: 1px solid #ccc;
        }
        table th
        {
            background-color: #F7F7F7;
            color: #333;
            font-weight: bold;
        }
        table th, table td
        {
            padding: 5px;
            border-color: #ccc;
        }
    </style>
</div>
</form>

C#

private int CustomerId
{
    get
    {
        return Convert.ToInt32(Request.QueryString["Id"]);
    }
}
private string constr = ConfigurationManager.ConnectionStrings["Constr"].ToString();
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.GetData();
    }
}

private void GetData()
{
    using (SqlConnection con = new SqlConnection(constr))
    {

        using (SqlCommand cmd = new SqlCommand("SELECT * FROM Customers WHERE CustomerId='" + CustomerId + "' ", con))
        {
            DataTable dt = new DataTable();
            using (SqlDataAdapter sda = new SqlDataAdapter(cmd))
            {
                sda.Fill(dt);
                lblId.Text = dt.Rows[0]["CustomerId"].ToString();
                txtName.Text = dt.Rows[0]["Name"].ToString();
                txtCountry.Text = dt.Rows[0]["Country"].ToString();
            }
        }
    }
}

Screenshot