[مصمم هاوي]

لمـاذا البطء في جلب البيانـات في الداتا قريدفيو على الرغم من البيانات لا تتعدي 10 اسطر

كود :

Private Sub FillCCourses()
        ' صب عرض الدرجــات حسب اســم المـادة
        If DataGridView1.Rows.Count = 0 Then Exit Sub
        For i As Integer = 0 To DataGridView1.Rows.Count - IIf(DataGridView1.AllowUserToAddRows, 2, 1)
            DataGridView1.Rows(i).Cells(4).Value = ""
            DataGridView1.Rows(i).Cells(5).Value = ""
            DataGridView1.Rows(i).Cells(6).Value = ""
        Next
        For i As Integer = 0 To DataGridView1.Rows.Count - IIf(DataGridView1.AllowUserToAddRows, 2, 1)
            Dim clasIndex As Integer = FormMin.ListBoxClas.SelectedIndex + 1
            Dim roomIndex As Integer = Me.Combroom.SelectedIndex + 1
            Dim sql As String = "select stID, on" & CombCourses.SelectedIndex + 1 & ", to" & CombCourses.SelectedIndex + 1 & ", tr" & CombCourses.SelectedIndex + 1 & " from TBL_Final1 where IDStudent=" & DataGridView1.Rows(i).Cells(0).Value & " and IDClas=" & FormMin.ListBoxClas.SelectedIndex + 1 & " and ClassroomID=" & Me.Combroom.SelectedIndex + 1 & " and SemesterID=" & Trim$(CombSemester.Text)
            Dim cm As New OleDb.OleDbCommand(sql, Con)
            cm.Parameters.AddWithValue("IDStudent", DataGridView1.Rows(i).Cells(0).Value)
            cm.Parameters.AddWithValue("IDClas", FormMin.ListBoxClas.SelectedIndex + 1)
            cm.Parameters.AddWithValue("ClassroomID", Me.Combroom.SelectedIndex + 1)
            cm.Parameters.AddWithValue("SemesterID", Trim$(CombSemester.Text))

            Try
                If Con.State = ConnectionState.Closed Then Con.Open()
                Dim dr As OleDb.OleDbDataReader = cm.ExecuteReader
                If dr.Read Then

                    DataGridView1.Rows(i).Cells(4).Value = dr(1)
                    DataGridView1.Rows(i).Cells(5).Value = dr(2)
                    DataGridView1.Rows(i).Cells(6).Value = dr(3)

                End If
                dr.Close()

            Catch ex As Exception
                MessageBox.Show("خطأ: " & ex.Message)
            Finally
                If Con.State = ConnectionState.Open Then Con.Close()
            End Try
        Next

    End Sub

---

واستخدمت هذا الكود ولكن لم يضبط معي

كود :

' صب عرض الدرجــات حسب اســم المـادة
        If DataGridView1.Rows.Count = 0 Then Exit Sub

        Dim sql As String = "select IDStudent, on" & CombCourses.SelectedIndex + 1 & ", to" & CombCourses.SelectedIndex + 1 & ", tr" & CombCourses.SelectedIndex + 1 & " from TBL_Final1 where IDClas=@IDClas and ClassroomID=@ClassroomID and SemesterID=@SemesterID"
        Dim dt As New DataTable()
        Using Con As New OleDb.OleDbConnection("...")
            Con.Open()
            Using cmd As New OleDb.OleDbCommand(sql, Con)
                cmd.Parameters.AddWithValue("@IDClas", FormMin.ListBoxClas.SelectedIndex + 1)
                cmd.Parameters.AddWithValue("@ClassroomID", Me.Combroom.SelectedIndex + 1)
                cmd.Parameters.AddWithValue("@SemesterID", Trim$(CombSemester.Text))

                Using adapter As New OleDb.OleDbDataAdapter(cmd)
                    adapter.Fill(dt)
                End Using
            End Using
        End Using

        For Each row As DataRow In dt.Rows
            For i As Integer = 0 To DataGridView1.Rows.Count - 1
                If DataGridView1.Rows(i).Cells(0).Value.ToString() = row("IDStudent").ToString() Then
                    DataGridView1.Rows(i).Cells(4).Value = row(1)
                    DataGridView1.Rows(i).Cells(5).Value = row(2)
                    DataGridView1.Rows(i).Cells(6).Value = row(3)
                    Exit For
                End If
            Next
        Next