getting columns from multiple tables into 1 datagridview in vb.net

One way would be to use a DataTable with all joined columns as datasource which you can fill with a DataAdapter:

Private Function GetDataSource() As DataTable
    Const sqlSelect As String = "SELECT a.Col1 AS aCol1,a.Col2 AS aCol2,b.Col1 AS bCol1,b.Col2 AS bCol2 " & _
                               "FROM dbo.TableA AS a INNER JOIN dbo.TableB AS b ON a.IdCol=b.aIdCol " & _
                               "ORDER BY aCol1 ASC,bCol1 ASC"
    Try
        Dim table = New DataTable()
        Using con = New MySqlConnection(My.Settings.MySqlConnectionString)
            con.Open()
            Using da = New MySqlDataAdapter(sqlSelect, con)
                da.Fill(table)
                Return table
            End Using
        End Using
    Catch ex As Exception
        ' log message instead '
        Throw ' don't use throw new Exception or throw ex '
    End Try
End Function

Now you can use this DataTable as DataSource for the DataGridView:

me.dataGridView1.DataSource = GetDataSource()