Hi onvar1196,

Refer below code.

HTML

<table>
    <% foreach (var c in this.item())
        { %>
    <tr>
        <td>
            <label><%=c.countryid%></label></td>
        <td>
            <input type="text" value='<%=c.countryname %>' /></td>
        <td>
            <input type="text" value='<%=c.photo%>' /></td>
        <td>
            <input type="radio" <%=c.countryname.ToLower() == "india" ? "checked" : "" %> /></td>
        <td>
            <input type="checkbox" <%=c.countryname.ToLower() != "india" ? "checked" : "" %> /></td>
        <td>
            <a href='Details.aspx?idno=<%=c.countryid %>'>Customer Detail</a> </td>
        <td>
            <button type="submit" name="btnSubmit_<%=c.countryid%>">View</button>
        </td>
    </tr>
    <tr>
        <td>
            <input type="text" value='<%=c.ctrypopulation%>' /></td>
        <td>
            <input type="text" value='<%=c.ctrymultiply%>' /></td>
        <td>
            <input type="text" value='<%=c.ctryresult%>' /></td>
        <td colspan="4">
            <input type="text" value='<%=(c.ctrymultiply * c.ctryresult).ToString("N2")+"%"%>' /></td>
    </tr>
    <% } %>
</table>

Code

public int ctryresult;
public int countryidx;
public string photox;
public string ulkeismix;

public List<Country> item()
{
    string sqlStatment = "select * from Country";
    string constr = System.Configuration.ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
    using (System.Data.SqlClient.SqlConnection con = new System.Data.SqlClient.SqlConnection(constr))
    {
        using (System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand(sqlStatment, con))
        {
            cmd.Connection.Open();
            System.Data.SqlClient.SqlDataReader reader = cmd.ExecuteReader();
            List<Country> emp = new List<Country>();
            while (reader.Read())
            {
                Country country = new Country();
                country.countryid = Convert.ToInt32(reader.GetValue(0));
                country.countryname = reader.GetValue(2).ToString();
                country.photo = reader.GetValue(1).ToString();
                country.ctrypopulation = reader.GetValue(3).ToString();
                country.ctrymultiply = Convert.ToInt32(reader.GetValue(4));

                emp.Add(country);
            }

            reader.Close();
            cmd.Connection.Close();
            return emp;
        }
    }
}

public class Country
{
    public int countryid { get; set; }
    public string countryname { get; set; }
    public string photo { get; set; }
    public string ctrypopulation { get; set; }
    public int ctrymultiply { get; set; }
    public int ctryresult { get; set; }
}

public List<Country> Item { get; set; }
protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        this.Item = this.item();
    }
    else
    {
        foreach (string item in Request.Form.AllKeys)
        {
            if (item.Contains("btnSubmit"))
            {
                string id = item.Split('_')[1].Trim();
                string sqlStatment = "SELECT * FROM country WHERE countryid=@Id";
                string constr = System.Configuration.ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
                using (System.Data.SqlClient.SqlConnection con = new System.Data.SqlClient.SqlConnection(constr))
                {
                    using (System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand(sqlStatment, con))
                    {
                        cmd.Parameters.AddWithValue("@Id", id);
                        cmd.Connection.Open();
                        System.Data.SqlClient.SqlDataReader reader = cmd.ExecuteReader();
                        if (reader.Read())
                        {
                            countryidx = Convert.ToInt32(reader.GetValue(0));
                            ulkeismix = reader.GetValue(1).ToString();
                            photox = reader.GetValue(2).ToString();
                        }

                        reader.Close();
                        cmd.Connection.Close();
                    }
                }
                break;
            }
        }
    }
}

Screenshot