TR : [MI-L] Fetch and table cursor position with Integrated Mapping

Christophe Brabant Wed, 02 Aug 2006 04:17:59 -0700

Title: Message

complete code, with datarows added

this changes absolutly nothing to my problem, but of course, with the first version of this code, dt.rows.count will always be 0 !

storing the rowid of each row, then fetching this rowid just before fetching the next row, solves the problem

the same code directly with MapBasic works fine, without storing and fetching RowId

Christophe

-----Message d'origine-----
De : [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] De la part de Christophe Brabant
Envoyé : mercredi 2 août 2006 09:21
À : [email protected]
Objet : [MI-L] Fetch and table cursor position with Integrated Mapping

Hi everyone, still a strange phenomen....

Does the ColumnInfo statment affect the current cursor position in a table ?

Look at the following sample, written in VB.NET :

========================================================================================

Public Sub Test(ByVal nom_layer As String)

        Dim msg As String
        Dim nom_col As String
        Dim dt As DataTable
        Dim nb_cols As Short
        Dim i As Short
        Dim type_col As Short
        Dim col_type As System.Type
        Dim nb_rows As Integer
        Dim j As Integer
        Dim log_val As String
        Dim rowid As Integer        ' **************FOR FIXING BUG***********
        Dim jj As Integer

Dim nr As DataRow

Try

            msg = "TableInfo(" + nom_layer + "," + TAB_INFO_NROWS.ToString + ")"
            jj = mapinfo.eval(msg)
            Console.WriteLine("nb rows into " + nom_layer + " : " + jj.ToString)

mapinfo.Do("Fetch First From " + nom_layer)

            jj = 0
            While (mapinfo.Eval("EOT(" + nom_layer + ")") = "F")
                mapinfo.Do("Fetch Next From " + nom_layer)
                jj += 1
            End While
            Console.WriteLine("nb rows processed at EOT : " + jj.ToString)

msg = "TableInfo(" + nom_layer + "," + TAB_INFO_NCOLS.ToString + ")"
nb_cols = mapinfo.eval(msg)

dt = New DataTable(nom_layer)

            For i = 1 To nb_cols
                msg = "ColumnInfo(" + nom_layer + "," + """" + "COL" + i.ToString + """" + "," _
                    + COL_INFO_NAME.ToString + ")"
                nom_col = mapinfo.eval(msg)

                msg = "ColumnInfo(" + nom_layer + "," + """" + nom_col + """" + "," _
                    + COL_INFO_TYPE.ToString + ")"
                type_col = mapinfo.eval(msg)

                Select Case type_col
                    Case COL_TYPE_CHAR
                        col_type = System.Type.GetType("System.String")
                    Case COL_TYPE_DECIMAL
                        col_type = System.Type.GetType("System.Decimal")
                    Case COL_TYPE_INTEGER
                        col_type = System.Type.GetType("System.Int32")
                    Case COL_TYPE_SMALLINT
                        col_type = System.Type.GetType("System.Int16")
                    Case COL_TYPE_DATE
                        col_type = System.Type.GetType("System.DateTime")
                    Case COL_TYPE_LOGICAL
                        col_type = System.Type.GetType("System.Boolean")
                    Case COL_TYPE_FLOAT
                        col_type = System.Type.GetType("System.Double")
                    Case COL_TYPE_GRAPHIC ' special column 'Obj' : nothing to do
                        GoTo next_column
                    Case Else               ' unknown type
                        MessageBox.Show("Table " + nom_layer _
                            + " : impossible de déterminer le type de la colonne '" + nom_col + "'.", _
                            "Erreur", MessageBoxButtons.OK, MessageBoxIcon.Error)
                End Select

dt.Columns.Add(nom_col, col_type)

next_column:

mapinfo.Do("Fetch First From " + nom_layer)

jj = 0
While (mapinfo.Eval("EOT(" + nom_layer + ")") = "F")

nr = dt.NewRow()

'rowid = mapinfo.eval(nom_layer + ".RowId") ' **************FOR FIXING BUG***********

                For i = 1 To nb_cols
                    msg = "ColumnInfo(" + nom_layer + "," + """" + "COL" + i.ToString + """" + "," _
                        + COL_INFO_TYPE.ToString + ")"
                    type_col = mapinfo.eval(msg)

                    Select Case type_col
                        Case COL_TYPE_CHAR, COL_TYPE_INTEGER, COL_TYPE_SMALLINT, COL_TYPE_DATE
                            nr(i - 1) = mapinfo.Eval(nom_layer + ".COL" + i.ToString)
                        Case COL_TYPE_LOGICAL
                            log_val = mapinfo.Eval(nom_layer + ".COL" + i.ToString)
                            If log_val = "T" Then
                                nr(i - 1) = True
                            Else
                                nr(i - 1) = False
                            End If
                        Case COL_TYPE_DECIMAL
                            Dim v As String
                            v = mapinfo.Eval(nom_layer + ".COL" + i.ToString)
                            nr(i - 1) = CType(v.Replace("."c, ","c), Decimal)
                        Case COL_TYPE_FLOAT
                            Dim v As String
                            v = mapinfo.Eval(nom_layer + ".COL" + i.ToString)
                            nr(i - 1) = CType(v.Replace("."c, ","c), Double)
                    End Select

dt.Rows.Add(nr)

'mapinfo.do("Fetch Rec " + rowid.ToString + " From " + nom_layer) ' **************FOR FIXING BUG***********

mapinfo.Do("Fetch Next From " + nom_layer)

jj += 1
End While

dt.AcceptChanges()

Console.WriteLine("table:" + dt.Rows.Count.ToString)

        Catch ex As Exception
            Fonctions_diverses.DisplayException(ex)
        End Try
    End Sub

========================================================================================

The output is :

nb rows into Monde7 : 252 ==> OK

nb rows processed at EOT : 252 ==> OK

table:133 (for example, or 365, or 411, etc....) ==> should be 252 !

========================================================================================

ColumnInfo statment, with COL_INFO_TYPE paramater, seems to affect current cursor position into the Monde7 table (world7 in english)

sometimes forward, sometimes backward, and by this way, due to the 'While (mapinfo.Eval("EOT(" + nom_layer + ")") = "F")' _expression_, the number of lines processed is greater or lower than the true value, who is 252 !

To fix that, I had to add the two lines marked with **************FOR FIXING BUG*********** in the code.

Any idea ?

Thank you - Chris

_______________________________________________
MapInfo-L mailing list
[email protected]
http://www.directionsmag.com/mailman/listinfo/mapinfo-l

_______________________________________________
MapInfo-L mailing list
[email protected]
http://www.directionsmag.com/mailman/listinfo/mapinfo-l

TR : [MI-L] Fetch and table cursor position with Integrated Mapping

Reply via email to