How to connect using odbc to as400 for vb.net - vb.net

Question

I'm trying to connect to a AS400 server using ODBC driver via vb.net application but the problem is that I am trying to fill a dataset and whenever I want to display the data I don't find any thing
This is my code:
Dim cn As OdbcConnection
Dim cm As OdbcCommand
Dim dm As OdbcDataAdapter
Sub ConnServer()
Try
cn = New OdbcConnection("DSN=AS400_CA;UID=root;PWD=*****;")
cn.Open()
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Ecriture Comptable")
End Try
End Sub
Public Function GetData(query As String) As DataTable
Try
cn = New OdbcConnection("DSN=AS400_CA;UID=root;PWD=*****;")
Dim cmd As OdbcCommand = New OdbcCommand(query, cn)
cn.Open()
Dim ds = New DataSet()
cmd.Connection = cn
dm.SelectCommand = cmd
dm.Fill(ds, "table")
Dim data = ds.Tables("table")
cn.Close()
Return data
Catch ex As Exception
con.Close()
Return New DataTable()
End Try
End Function
```

Answer 1

I do not know what provider you are using. Check https://www.connectionstrings.com/as-400/ to check your connection string. I do not see a connection string that matches the syntax of your string.
I have no idea of select strings in AS400 so I just used a standard Sql string. Put your try/catch in the UI code so you can show a message box with the error.
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim dt As DataTable
Try
dt = GetData("Select * From SomeTable;")
Catch ex As Exception
MessageBox.Show(ex.Message)
Exit Sub
End Try
DataGridView1.DataSource = dt
End Sub
In your function you are returning a DataTable so why are you messing with a DataSet? Just load the DataTable. Connections, Commands, and DataReaders all need to be disposed. Using...End Using blocks handle closing and disposing even if there is an error.
Public Function GetData(query As String) As DataTable
Dim dt As New DataTable
Using cn = New OdbcConnection("DSN=AS400_CA;UID=root;PWD=*****;"),
cmd As OdbcCommand = New OdbcCommand(query, cn)
cn.Open()
Using reader = cmd.ExecuteReader
dt.Load(reader)
End Using
End Using
Return dt
End Function

Answer 2

this C# code worked for me.
I am using the IBM access client solutions 64bit ODBC driver.
using System;
using System.Data.Odbc;
using System.Data;
namespace IntroUI
{
class Program
{
static void Main(string[] args)
{
// make sure using 64 bit IBM i Access ODBC driver
var conn = OpenConnection("dsn", "user", "pass");
OdbcCommand cmd = conn.CreateCommand();
var query = "select a.* from qrpglesrc a";
var table = GetData( conn, query ) ;
var numRows = table.Rows.Count ;
for( var ix = 0 ; ix < numRows ; ++ix )
{
var row = table.Rows[ix] ;
var srcdta = row.ItemArray[2] ;
Console.WriteLine( srcdta ) ;
if ( ix > 20 )
break ;
}
conn.Close( ) ;
}
// InDsn is the dsn from the odbc administration window
static OdbcConnection OpenConnection( string InDsn, string InUser, string InPwd )
{
string connString = "DSN=" + InDsn + "; UID=" + InUser +
"; PWD=" + InPwd + ";" ;
OdbcConnection conn = new OdbcConnection( connString ) ;
conn.Open( ) ;
return conn ;
}
static DataTable GetData( OdbcConnection conn, string query )
{
OdbcDataAdapter dm = new OdbcDataAdapter() ;
OdbcCommand cmd = new OdbcCommand(query, conn);
DataSet ds = new DataSet( ) ;
dm.SelectCommand = cmd ;
dm.Fill( ds, "table") ;
var data = ds.Tables["table"] ;
return data ;
}
}
}