Record is not showing in GridView.
<asp:GridView ID="GridView2" runat="server" DataKeyNames="AdmissionNo" OnRowDataBound="OnRowDataBound" CssClass="table table-striped table-bordered table-hover">
</asp:GridView>
 
    private static DataTable GetData(string query)
    {
        string strConnString = ConfigurationManager.ConnectionStrings["ConStr"].ConnectionString;
        using (SqlConnection con = new SqlConnection(strConnString))
        {
            using (SqlCommand cmd = new SqlCommand())
            {
                cmd.CommandText = query;
                using (SqlDataAdapter sda = new SqlDataAdapter())
                {
                    cmd.Connection = con;
                    sda.SelectCommand = cmd;
                    using (DataSet ds = new DataSet())
                    {
                        DataTable dt = new DataTable();
                        sda.Fill(dt);
                        return dt;
                    }
                }
            }
        }
    }
    protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowType == DataControlRowType.DataRow)
        {
            string Id = GridView2.DataKeys[e.Row.RowIndex].Value.ToString();
            GridView2.DataSource = GetData(string.Format("select fc.AdmissionNo,NetBal,Paid,RemBal,FeesMonth from tblFeesCollection as fc inner join tblStdReg as sr on fc.AdmissionNo=sr.AdmissionNo  where sr.ClassID='55' and RemBal > 0 and  FeeID IN (SELECT MAX(FeeID) FROM tblFeesCollection where fc.AdmissionNo= '{0}')", Id));
            
            GridView2.DataBind(); 
        }
    }
and data is here
| AdmissionNo | Month | Recievable | NetBal | Paid | RemBal | 
| R-01 | Jan | 1000 | 1000 | 600 | 400 | 
| R-01 | Jan | 1000 | 400 | 200 | 100 | 
| R-02 | Jan | 1000 | 1000 | 400 | 600 | 
| R-02 | Jan | 1000 | 600 | 300 | 300 | 
| R-02 | Jan | 1000 | 300 | 200 | 100 | 
| R-03 | Jan | 1000 | 1000 | 500 | 500 | 
| R-03 | Jan | 1000 | 500 | 200 | 300 | 
| R-03 | Jan | 1000 | 300 | 150 | 150 | 
| R-04 | Jan | 1000 | 1000 | 700 | 300 | 
| R-05 | Jan | 1000 | 1000 | 800 | 200 |