DllCall gives an error number 3

[kcvinu]

Hi all,

I have made a dll file in vb.net with a single function which returns a List(Of String). I have double check the name of the function. But it gives me an error number3. That means, function  not found in the dll file. What to do ?

this is my code

Local $dllPath = "E:\VB Works\OLEDB COM Works\TestApp\OLEDBtest\OLEDBtest\bin\Debug\OLEDBtest.dll"
Local $DBpath = "E:\KSEB METER READING\MRDB.accdb"
Local $SQL_Query = "SELECT Reading FROM DMR"
Local $hDll = DllOpen($dllPath)

Local $CallingDll = DllCall($hDll,"str","OneColumnFromDB","str",$DBpath,"str", $SQL_Query)

if @error Then
    Alert(@error)
Else
    Alert("OK")
EndIf
Exit

DllClose($hDll)

And this is vb,net code

Imports System.Data.OleDb
Public Class SelectFromDB
    Public Function OneColumnFromDB(ByVal DBpath As String, ByVal SQLstr As String) As List(Of String)
        Dim RetValues As New List(Of String)
        Dim Conn As New OleDb.OleDbConnection
        Dim Cnstr As String = "Provider = Microsoft.ACE.OLEDB.12.0;Data Source = " & DBpath
        Conn.ConnectionString = Cnstr
        Dim Cmd As New OleDb.OleDbCommand(SQLstr, Conn)
        Try
            Conn.Open()
            Dim Sdr As OleDb.OleDbDataReader = Cmd.ExecuteReader
            While Sdr.Read()
                RetValues.Add(Sdr.Item(0))
            End While
            Sdr.Close()
            Cmd.Dispose()
            Conn.Close()

        Catch ex As Exception
            RetValues.Add(ex.Message)
            Conn.Close()
        End Try
        Return RetValues
    End Function
End Class

 

Edited July 26, 2015 by kcvinu

[trancexx]

To use DllCall you have to find a way to export your function from the dll. It's not as trivial as one could think in case of VB.NET

[kcvinu]

@trancexx , You mean, my vb.net code is wrong. do you ? 

[trancexx]

No, I don't.

[guinness]

I didn't take trancexx's comment as being that either. As mentioned before I am not a VB.NET dev, but in C# we would register the assembly using regasm.exe. See >> https://www.autoitscript.com/forum/topic/166704-net-compiled-dll-assembly-in-autoit-the-simple-approach/

[kcvinu]

@guinness, Yes, i know about regasm. But i thought that it's only needed when we want to create a COM dll. Now, you are saying that, i need to register this dll with regasm. Ok. Let me try. Thank you  

@guinness , Thank you for the link. In that post, you said that to copy paste the dll from Debug dir to Script dir. In my case, dll file is still in the Debug dir. But i wonder, my function only returns error number 3, that means "Function not found in the dll file". Not the dll. 

Edited July 27, 2015 by kcvinu