Question

I’ve VB.NET function that reads data from an Excel sheet and adds rows in a Datatable.

Private Function LoadDataToRows(ByVal TableName As DataTable, ByVal Header As System.Collections.Specialized.StringCollection) As Boolean
       Dim HeaderDataExcel As String = String.Empty    'Data Header
       For r As Integer = 1 To RangeDataArray.Rows.Count
            Dim NewRow As DataRow = TableName.NewRow
            For c As Integer = 1 To RangeDataArray.Columns.Count
                If Not (IsNothing(DirectCast(ActiveSheetToManipulate.Cells.Item(r + DataStartRow, c), Excel.Range).Value)) Then
                    Dim ValueToLoad As String = TryCast(ActiveSheetToManipulate.Cells.Item(r + DataStartRow, c), Excel.Range).Value.ToString

                    HeaderDataExcel = TryCast(ActiveSheetToManipulate.Cells.Item(DataStartRow, c), Excel.Range).Value.ToString
                    Dim indice As Integer = Header.IndexOf(HeaderDataExcel)
                    TableName.NewRow(indice) = ValueToLoad
                Else
                    'Todo
                End If
            Next
            TableName.Rows.Add(NewRow)
        Next
        Return True
    End Function

But no data was add to the table. Any suggestions?

Answer 1

I’m not a VB.NET programmer but you probably need to change the DataTable parameter to be passed ByRef rather than ByVal

In addition is the syntax for populating the NewRow columns correct? You should be using the created new data row instance rather than using TableName.NewRow?

I thought it was more like:

Dim newRow As DataRow = TableName.NewRow()

newRow ("ColumnName") = "MyNewValue"  ' Add specifying column name
newRow (2) = "AnotherValue" ' Add specifying column index

TableName.Rows.Add(newRow)

So your code would be something like the following (note I’ve changed the name of the new row variable because I think that’s causing part of your confusion)

        Dim rowToAdd As DataRow = TableName.NewRow()
        For c As Integer = 1 To RangeDataArray.Columns.Count
            If Not (IsNothing(DirectCast(ActiveSheetToManipulate.Cells.Item(r + DataStartRow, c), Excel.Range).Value)) Then
                Dim ValueToLoad As String = TryCast(ActiveSheetToManipulate.Cells.Item(r + DataStartRow, c), Excel.Range).Value.ToString

                HeaderDataExcel = TryCast(ActiveSheetToManipulate.Cells.Item(DataStartRow, c), Excel.Range).Value.ToString
                Dim indice As Integer = Header.IndexOf(HeaderDataExcel)
                rowToAdd(indice) = ValueToLoad
            Else
                'Todo
            End If
        Next
        TableName.Rows.Add(rowToAdd)