Increase the performance of program

Private Sub btnSetGrade_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSetGrade.Click
       Dim CollIndex As Integer = 0, TempID As Integer = 0, SaveID As Integer = 0
       Dim ColName As String = "", TempIDTotal As String = "", QryGetTot As String = ""
       cmdExecute("delete from tbTestHeading")
       cmdExecute("insert into   tbTestHeading (tempID) values (1)")

       '==================Get Subject Name of Current Session=================================
       Dim dsSession As DataSet = DirectCast(cmdGetData("SELECT DISTINCT [session],class_id FROM  testmaster  WHERE   (Srno IN (SELECT srno  FROM  testdetail WHERE (stcode =" & txtStudentCode.Text & ") ORDER BY srno)) order by [session]"), DataSet)
       Dim sessionID As String = "", classID As String = ""
       For i = 0 To dsSession.Tables(0).Rows.Count - 1
           sessionID = sessionID & "'" & dsSession.Tables(0).Rows(i)(0) & "',"
           classID = classID & dsSession.Tables(0).Rows(i)(1) & ","
       Next
       sessionID = sessionID.Substring(0, sessionID.Length - 1)
       classID = classID.Substring(0, classID.Length - 1)

       '============Get Test names and Insert in table====================
       Dim dsTestName As DataSet = DirectCast(cmdGetData("SELECT DISTINCT testmaster.test, testgrade.testOrder FROM  (testmaster INNER JOIN  testgrade ON testmaster.test = testgrade.testName) WHERE  (testmaster.class_id IN (" & classID & ")) AND (testmaster.[session] IN (" & sessionID & ")) ORDER BY testgrade.testOrder"), DataSet)
       If dsTestName.Tables(0).Rows.Count > 0 Then
           For iTN = 0 To dsTestName.Tables(0).Rows.Count - 1
               CollIndex = CollIndex + 1
               cmdExecute("update tbTestHeading set R" & CollIndex & "='" & dsTestName.Tables(0).Rows(iTN)("test") & "' where tempID=1")
               QryGetTot = QryGetTot & "R" & CollIndex & ","
           Next
           QryGetTot = "R" & CollIndex + 2 & "," & QryGetTot
       End If
       '=============================End Test Name=============================================

       '======================Get Max Temp ID============================================
       Dim MaxID As Integer = Convert.ToInt32(getMaxID("tempID", "tbTestHeading"))


       For iSn = 0 To dsSession.Tables(0).Rows.Count - 1
           MaxID = MaxID + 1
           '==========Get year on based of Session and save===================
           Dim dsYear As DataSet = DirectCast(cmdGetData("SELECT startdate,enddate  FROM SessionMaster where srno=" & dsSession.Tables(0).Rows(iSn)("session")), DataSet)
           Dim StartYear = Year(dsYear.Tables(0).Rows(0)("startdate"))
           Dim EndYear = Year(dsYear.Tables(0).Rows(0)("enddate"))
           Dim Session = StartYear & "-" & EndYear
           cmdExecute("insert into   tbTestHeading (tempID,sessionName) values (" & MaxID & ",'" & Session & "')")
           SaveID = MaxID
           TempIDTotal = TempIDTotal & MaxID & ","
           '=====================End Year========================================

           '===================Get Subject name of Current session========================
           Dim dsSubjectName As DataSet = DirectCast(cmdGetData("SELECT DISTINCT Subject_master.shortName FROM  ((testdetail INNER JOIN  testmaster ON testdetail.srno = testmaster.Srno) INNER JOIN Subject_master ON testmaster.sub_id = Subject_master.srno) WHERE (testdetail.stcode =" & txtStudentCode.Text & ") AND (testmaster.[session] = '" & dsSession.Tables(0).Rows(iSn)("session") & "') "), DataSet)
           For iSubN = 0 To dsSubjectName.Tables(0).Rows.Count - 1
               MaxID = MaxID + 1
               cmdExecute("insert into   tbTestHeading (tempID,subjectName) values (" & MaxID & ",'" & dsSubjectName.Tables(0).Rows(iSubN)("shortName") & "')")

           Next 'Subject Name For End
           '======================End Subject Name====================

           '===========Get Marks of Student in Particular Session====================
           Dim dsMarks As DataSet = DirectCast(cmdGetData("SELECT testdetail.marks, testmaster.test, Subject_master.shortName, testmaster.class_id, testmaster.[section], testdetail.[max] FROM (((testdetail INNER JOIN  testmaster ON testdetail.srno = testmaster.Srno) INNER JOIN Subject_master ON testmaster.sub_id = Subject_master.srno) INNER JOIN testgrade ON testmaster.test = testgrade.testName) WHERE (testdetail.stcode = " & txtStudentCode.Text & ") AND (testmaster.[session] = '" & dsSession.Tables(0).Rows(iSn)("session") & "') ORDER BY testgrade.testOrder, Subject_master.srno "), DataSet)
           Dim MaxMarks As Integer = 0

           '===========Get Maximum marks =======================================
           Dim dsMax As DataSet = DirectCast(cmdGetData("SELECT DISTINCT testmaster.test, testmaster.[max] FROM  (testmaster INNER JOIN  testdetail ON testmaster.Srno = testdetail.srno) WHERE  (testdetail.stcode =" & txtStudentCode.Text & ") AND (testmaster.[session] = '" & dsSession.Tables(0).Rows(iSn)("session") & "') AND (testmaster.[section] = '" & dsMarks.Tables(0).Rows(0)("section") & "') AND (testmaster.class_id =" & dsMarks.Tables(0).Rows(0)("class_id") & ")"), DataSet)
           For iMax = 0 To dsMax.Tables(0).Rows.Count - 1
               Try
                   MaxMarks = MaxMarks + dsMax.Tables(0).Rows(iMax)("max")
               Catch ex As Exception
                   MaxMarks = 0
               End Try
           Next
           '=============End Maximum Marks=============================================

           For iM = 0 To dsMarks.Tables(0).Rows.Count - 1

               '============================Get Column Name===================================
               Dim dsColumnName As DataSet = DirectCast(cmdGetData("select * from tbTestHeading where tempID=1"), DataSet)
               For iCN = 0 To dsColumnName.Tables(0).Columns.Count - 1
                   If Convert.ToString(dsMarks.Tables(0).Rows(iM)("test")) = Convert.ToString(dsColumnName.Tables(0).Rows(0)(iCN)) Then
                       ColName = dsColumnName.Tables(0).Columns(iCN).ColumnName
                       Exit For
                   End If
               Next 'Column Name For End

               '================Change Here==========================
               '================Get Grade according Marks==============
               Dim Grade As String = ""
               Dim gradeMarks As Decimal = 0
               If Convert.ToInt32(dsMarks.Tables(0).Rows(iM)("marks")) <> 0 Then
                   gradeMarks = Convert.ToInt32(dsMarks.Tables(0).Rows(iM)("marks")) * 100 / Convert.ToInt32(Convert.ToInt32(dsMarks.Tables(0).Rows(iM)("max")))

                   Dim dsGrade As DataSet = DirectCast(cmdGetData("select * from SessionGrade"), DataSet)
                   For iG = 0 To dsGrade.Tables(0).Rows.Count - 1
                       If gradeMarks >= dsGrade.Tables(0).Rows(iG)("mf") And gradeMarks <= dsGrade.Tables(0).Rows(iG)("mt") Then
                           Grade = "\" & dsGrade.Tables(0).Rows(iG)("grade")
                           Exit For
                       End If
                   Next
               Else
                   Grade = ""
               End If
               '==============End Grade============================
               '================End Change=============================

               '================Set Marks of Current subject in curretn Test in Current Session===================

               '=============== Change here =====================
               Dim qry As String = "update tbTestHeading set " & ColName & "='" & dsMarks.Tables(0).Rows(iM)("marks") & Grade & "' where subjectName='" & dsMarks.Tables(0).Rows(iM)("shortName") & "' and tempID>" & SaveID
               '================End Change=========================
               cmdExecute(qry)
               cmdExecute("update tbTestHeading set R" & CollIndex + 2 & "='" & MaxMarks & "' where subjectName='" & dsMarks.Tables(0).Rows(iM)("shortName") & "' and tempID>" & SaveID)


           Next 'Marks For End

       Next 'Session For End

       '==========================Total=================================================
       CollIndex = CollIndex + 1
       cmdExecute("update tbTestHeading set R" & CollIndex & "='Total' where tempID=1")
       cmdExecute("update tbTestHeading set R" & CollIndex + 1 & "='Percntage' where tempID=1")
       TempIDTotal = TempIDTotal.Substring(0, TempIDTotal.Length - 1)
       QryGetTot = QryGetTot.Substring(0, QryGetTot.Length - 1)
       Dim qryTot As String = "select tempID," & QryGetTot & " FROM  tbTestHeading WHERE  (NOT (tempID IN (1," & TempIDTotal & ")))"
       Dim dsTotal As DataSet = DirectCast(cmdGetData(qryTot), DataSet)
       For iTR = 0 To dsTotal.Tables(0).Rows.Count - 1
           Dim TotMarks As Decimal = 0
           For iTC = 2 To dsTotal.Tables(0).Columns.Count - 1

               '===================== Change here =======================
               Dim MarksR As String = Convert.ToString(dsTotal.Tables(0).Rows(iTR)(iTC))
               If MarksR <> "" Then
                   Dim a = MarksR.IndexOf("\")
                   MarksR = MarksR.Substring(0, a)

                   Dim marks As Decimal = 0
                   Try
                       marks = Convert.ToDecimal(MarksR)
                   Catch ex As Exception
                       marks = 0
                   End Try

                   TotMarks = TotMarks + marks
               End If
               '=================End Change==============================
           Next


           '==============Set Total Marks===================
           cmdExecute("update tbTestHeading set R" & CollIndex & "='" & TotMarks & "' where tempID=" & dsTotal.Tables(0).Rows(iTR)(0))

           '===================Set Average======================================
           Dim Avg As Decimal = TotMarks / Convert.ToInt32(dsTotal.Tables(0).Rows(iTR)(1)) * 100
           Avg = Math.Round(Avg, 2)
           cmdExecute("update tbTestHeading set R" & CollIndex + 1 & "='" & Avg & "' where tempID=" & dsTotal.Tables(0).Rows(iTR)(0))
       Next
       MsgBox("Success")
   End Sub