Repeater Data in Modal

protected void ddlBook_SelectedIndexChanged(object sender, EventArgs e)
{
    try
    {
        if (ddlBook.SelectedItem.Value != "")
        {
            GetSession(Convert.ToInt32(ddlBook.SelectedItem.Value));

            List StudentCollection = new List();
            BALGroupParticipant bALGroupParticipant = new BALGroupParticipant();
            List objStudentList = bALGroupParticipant.GetGroupParticipantsList(Convert.ToInt32(hdfGroupID.Value));
            BALStudents bALStudents = new BALStudents();
            if (objStudentList != null)
            {
                foreach (var colum1 in objStudentList)
                {
                    StudentCollection.Add(colum1.StudentID.ToString());
                }
            }

            Int32 BookID = Convert.ToInt32(ddlBook.SelectedItem.Value);
            BALSessionDeliveryParticipant bALSessionDeliveryParticipant = new BALSessionDeliveryParticipant();
            View_SessionDeliveryParticipant_Detailed Result = bALSessionDeliveryParticipant.GetSessionDeliveryParticipantBookHistory(Convert.ToInt32(ddlBook.SelectedItem.Value), StudentCollection);
            if (Result != null)
            {
                // Add this line to show the modal with the data
                Page.ClientScript.RegisterStartupScript(this.GetType(), "ShowModal", "");

                // Set the data to be displayed in the modal
                lblModalTitle.Text = "For Your Information";
                lblModalBody.Text = Result.Name + " in Session - " + Result.SessionDeliveryNo + " dated : " + Convert.ToDateTime(Result.SessionDate).ToString("dd-MM-yyyy");
                divModalAlert.Attributes["class"] = "alert alert-info";
            }
        }
        else
        {
            GetSession(0);
        }
        BindData(Convert.ToInt32(hdfGroupID.Value), Convert.ToInt32(hdfModuleID.Value), false);
    }
    catch (Exception ex)
    {
        Utility.SaveErrorLog(ex.Message, System.IO.Path.GetFileName(Request.Path), System.Reflection.MethodBase.GetCurrentMethod().Name, Convert.ToInt32(hdfLoginCode.Value));
        ShowMessage("Oops...", ex.Message, "error");
    }
}