How to display query results from SQL server in VB?

Question

I am trying to display query results from SQL server in VB. I wrote following code, but not getting how to "Just display the results";

 Public Function ConnectToSQL() As String
        Dim con As New SqlConnection
Try
            con.ConnectionString = "Data Source=(local);Initial Catalog=TestDatabase;Persist Security Info=True;User ID=sa;Password=afm"
            Dim cmd As New SqlCommand("SELECT username FROM users WHERE username='user'", con)
            con.Open()
            Console.WriteLine("Connection Opened")

            ' Execute Query
            Dim reader As SqlDataReader = cmd.ExecuteReader()
            While reader.Read()
                Console.WriteLine(String.Format("{0}, {1}", _
                   reader(0), reader(1)))

            End While
        Catch ex As Exception
            MessageBox.Show("Error while connecting to SQL Server." & ex.Message)
        Finally
            con.Close() 'Whether there is error or not. Close the connection.
        End Try
        Return reader
    End Function

Can any one guide? Thank you

Solution

I corrected a few things and now your function works fine for me:

Public Function ConnectToSQL() As String
    Dim con As New SqlConnection
    Dim reader As SqlDataReader
    Try
        con.ConnectionString = "Data Source=(local);Initial Catalog=TestDatabase;Persist Security Info=True;User ID=sa;Password=afm"
        Dim cmd As New SqlCommand("SELECT username, WindowsLogin FROM users WHERE username='user'", con)
        con.Open()
        Console.WriteLine("Connection Opened")

        ' Execute Query    '
        reader = cmd.ExecuteReader()
        While reader.Read()
            Console.WriteLine(String.Format("{0}, {1}", _
               reader(0), reader(1)))
            'NOTE: (^^) You are trying to read 2 columns here, but you only        '
            '   SELECT-ed one (username) originally...                             '
            ' , Also, you can call the columns by name(string), not just by number '

        End While
    Catch ex As Exception
        MessageBox.Show("Error while connecting to SQL Server." & ex.Message)
    Finally
        con.Close() 'Whether there is error or not. Close the connection.    '
    End Try
    'Return reader { note: reader is not valid after it is closed }          '
    Return "done"
End Function

Let me know if you have any questions.

Comments

[Andomar]

Please read a tutorial and post less questions

[mola10]

csharp-station.com/Tutorials/AdoDotNet/Lesson04.aspx Listing 1

[AbdulAziz]

@mola10 Thank you for your answer, can you guide me something in VB.Thanks

[mola10]

google + "vb SqlDataReader" == first position =) Link: msdn.microsoft.com/en-us/library/haa3afyz(v=vs.71).aspx

[Joel Coehoorn]

Does this even compile? You're returning an sqldatareader object from a method declared to return a string.

[João Paladini]

what do you want to display it to? The console?

[AbdulAziz]

Thank you very much. It really helps me and its working as well. And I also know from your answer, where I am mistaken. Thank you once again.