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

Wed, 02 Aug 2006 00:23:59 -0700

Title: Message
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
 
        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:
 
            Next
 
            mapinfo.Do("Fetch First From " + nom_layer)
 
            jj = 0
            While (mapinfo.Eval("EOT(" + nom_layer + ")") = "F")
                '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)
                Next
 
                '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
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