How to get the values from excel to datatable?

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C#

ASP.NET

Hi,

I have an Excel Sheet in which there are some columns in which some columns are fixed and some columns are dynamic that means i have a students in class if the class changes the number of student also changes.So i have a problem here i wrote the code as below

foreach (DataRow row in dtSub.Rows)
                {
                    objSubExamSubjectMarks = new SpGetAllStudentSubExamMarks_Result();
                    if (row["ExamSubMapId"] != DBNull.Value)
                        objSubExamSubjectMarks.ExamSubMapId = Convert.ToInt32(row["ExamSubMapId"]);
                    if (row["CourseId"] != DBNull.Value)
                        objSubExamSubjectMarks.CourseId = Convert.ToInt32(row["CourseId"]);
                    if (row["ExamCourseMappingId"] != DBNull.Value)
                        objSubExamSubjectMarks.ExamCourseMappingId = Convert.ToInt32(row["ExamCourseMappingId"]);
                    if (row["ExamTypeId"] != DBNull.Value)
                        objSubExamSubjectMarks.ExamTypeId = Convert.ToInt32(row["ExamTypeId"]);
                    if (row["SubjectId"] != DBNull.Value)
                        objSubExamSubjectMarks.SubjectId = Convert.ToInt32(row["SubjectId"]);
                    if (row["SubSectionId"] != DBNull.Value)
                        objSubExamSubjectMarks.SubSectionId = Convert.ToInt32(row["SubSectionId"]);
                    if ((row["Description"] != DBNull.Value) && (!string.IsNullOrEmpty(row["Description"].ToString())))
                        objSubExamSubjectMarks.Description = Convert.ToString(row["Description"]);
                    List<student> lstStudents =
                        objGenlogic.getAllStudents(Convert.ToDateTime(ddlBulkAcad.SelectedValue))
                            .FindAll(
                                F =>F.SectionId == Convert.ToInt32(ddlBulkSec.SelectedValue) &&
                                    F.CourseId == Convert.ToInt32(row["CourseId"]));
                    objSubExamSubjectMarks.AcademicYear = ddlBulkAcad.SelectedValue;
                    foreach (Student objStudent in lstStudents)
                    {

                        if (row[objStudent.FullName + "-" + objStudent.StudentId] != DBNull.Value)
                            objSubExamSubjectMarks.MarksObtained =
                                Convert.ToString(row[objStudent.FullName + "-" + objStudent.StudentId]);
                        objSubExamSubjectMarks.StudentId = objStudent.StudentId;
                        
                        lstSubExamData.Add(objSubExamSubjectMarks);
                    }

                }

My Problem here is i am saving the results in lstSubExamData but it is showing the same studentid for all the records in the list.
Can anyone help me?
Thanks in advance