AUTO NUMBER GENERATION

OleDbConnection cn = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=..\..\..\database.mdb");

cn.open();

DataSet ds = new DataSet();

OleDbDataAdapter da = new OleDbDataAdapter("SELECT iif(max(fieldname)=Null,1,max(field name) +1) as [Number] from Tablename", cn);

da.Fill(ds);

if (ds.Tables[0].Rows.Count > 0)
{

textBox1.Text= ds.Tables[0].Rows[0]["Number"].ToString();

}

cn.close();