[Solved] ASP.Net GridView CSS (Style) changed after Paging

Please help my GridView does not display well after clicking on the next page on the GridView.

when i click on page 2 or next pages this is what is displayed.

Private Sub BindGridP1P2()
    Dim constr As String = ConfigurationManager.ConnectionStrings("SMIS2022ConnectionString").ConnectionString
    Using con As New SqlConnection(constr)
        Using cmd As New SqlCommand("entermarksP1P2")
            ' Using sda As New SqlDataAdapter()
            Using sda As SqlDataAdapter = New SqlDataAdapter(cmd)
 
                    cmd.CommandType = CommandType.StoredProcedure
                    cmd.Parameters.Add("@c", SqlDbType.NVarChar).Value = DropDownList1Class.SelectedItem.Text
                    cmd.Parameters.Add("@st", SqlDbType.NVarChar).Value = DropDownList2Stream.SelectedItem.Text
                    cmd.Parameters.Add("@sbj", SqlDbType.NVarChar).Value = DropDownList3Subject.SelectedItem.Text
 
                    cmd.Connection = con
                    sda.SelectCommand = cmd
                    Using dt As New DataTable()
                        sda.Fill(dt)
                        StudentGridMarks.DataSource = dt
                        StudentGridMarks.DataBind()
 
 
                End Using
                End Using
            End Using
    End Using
End Sub

Protected Sub OnPageIndexChanging(sender As Object, e As GridViewPageEventArgs)
    StudentGridMarks.PageIndex = e.NewPageIndex 
    If khold = "hold" Then
    End If
    BindGridP1P2()
End Sub