How to use the dataTable object to read a worksheet directly into an array without opening the excel file and without looping through every cell

Question

I am using vb.net 2012 v14.8.4084

This simple function is meant to dump all content from an excel file's sheet1 into an array

And then print this array to console

This code fails to compile due to use of "AsEnumerate" on line 27

I am unsure whether it fails due to a syntax error, a declaration error, my compiler being too old (can't change it)

Here is the error message

readfromxls.vb(27) : error BC30456: 'AsEnumerable' is not a member of 'System.Data.DataTable'.

                Dim data As String() = dataTable.AsEnumerable().SelectMany(Function(row) row.ItemArray.Select(Function(item) item.ToString())).ToArray()

Here is the code itself

Imports System.Data.OleDb

Module Module1

Public Function ReadWorksheetData(ByVal filePath As String, ByVal worksheetName As String) As String()
    ' Determine the connection string based on the file extension
    Dim connectionString As String
    If System.IO.Path.GetExtension(filePath).ToLower() = ".xlsx" Then
        connectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & filePath & ";Extended Properties='Excel 12.0 Xml;HDR=YES;IMEX=1;';"
    Else
        connectionString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & filePath & ";Extended Properties='Excel 8.0;HDR=YES;IMEX=1;';"
    End If

    ' Create a new connection
    Using connection As New OleDbConnection(connectionString)
        connection.Open()

        ' Create a command to select all data from the worksheet
        Using command As New OleDbCommand("SELECT * FROM [" & worksheetName & "$]", connection)
            ' Execute the command and get the data
            Using reader As OleDbDataReader = command.ExecuteReader()
                ' Load the data into a DataTable
                Dim dataTable As New System.Data.DataTable()
                dataTable.Load(reader)

                ' Convert the DataTable to a string array
                Dim data As String() = dataTable.AsEnumerable().SelectMany(Function(row) row.ItemArray.Select(Function(item) item.ToString())).ToArray()

                ' Return the cell data as a string array
                Return data
            End Using
        End Using
    End Using
End Function


Public Sub TestReadWorksheetData()
    ' Specify the file path and worksheet name
    Dim filePath As String = "testfile.xlsx"
    Dim worksheetName As String = "Sheet1"

    ' Call the function to read the worksheet data
    Dim data As String() = ReadWorksheetData(filePath, worksheetName)

    ' Loop through the string array and output each string to the console
    For Each str As String In data
        Console.WriteLine(str)
    Next
End Sub

public sub main()
    TestReadWorksheetData()
end sub

End Module

Correction, the error message was about "AsEnumerable" not "AsEnumerate"

Here is the compiler error message

H:\ow\readfromxls>vbc /nologo readfromxls.vb
H:\ow\readfromxls\readfromxls.vb(27) : error BC30456: 'AsEnumerable' is not a member of 'System.Data.DataTable'.

                Dim data As String() = dataTable.AsEnumerable().SelectMany(Function(row) row.ItemArray.Select(Function(item) item.ToString())).ToArray()
                                       ~~~~~~~~~~~~~~~~~~~~~~

Answer 1

The function in question is AsEnumerable, not AsEnumerate. The idea is that it generates an IEnumerable(Of DataRow), because LINQ operates on objects that implement IEnumerable(Of T). That method is part of the LINQ to DataSet provider, so you need to make sure that your project has the appropriate reference to use that provider. Here is the documentation for that method for .NET Framework 4.5. As with all type/member documentation, it specifies what assembly you need to reference in order to access it. In this case, it's System.Data.DataSetExtensions.dll, which is basically the LINQ to DataSet library.