First off, don;t do it like that! Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Always use Parameterized queries instead.
When you concatenate strings, you cause problems because SQL receives commands like:
SELECT * FROM MyTable WHERE StreetAddress = 'Baker's Wood'
The quote the user added terminates the string as far as SQL is concerned and you get problems. But it could be worse. If I come along and type this instead: "x';DROP TABLE MyTable;--" Then SQL receives a very different command:
SELECT * FROM MyTable WHERE StreetAddress = 'x';DROP TABLE MyTable;
Which SQL sees as three separate commands:
SELECT * FROM MyTable WHERE StreetAddress = 'x';
A perfectly valid SELECT
DROP TABLE MyTable;
A perfectly valid "delete the table" command
And everything else is a comment.
So it does: selects any matching rows, deletes the table from the DB, and ignores anything else.
So ALWAYS use parameterized queries! Or be prepared to restore your DB from backup frequently. You do take backups regularly, don't you?
Secondly, a SELECT command is a query - so using ExecuteNonQuery will not work at all - you need to use a DataAdapter or DataReader instead:
Using con As New SqlConnection(strConnect)
con.Open()
Using cmd As New SqlCommand("SELECT iD, description FROM myTable", con)
Using reader As SqlDataReader = cmd.ExecuteReader()
While reader.Read()
Dim id__1 As Integer = CInt(reader("iD"))
Dim desc As String = DirectCast(reader("description"), String)
Console.WriteLine("ID: {0}" & vbLf & " {1}", iD, desc)
End While
End Using
End Using
End Using
Using con As SqlConnection = New SqlConnection(strConnect)
con.Open()
Using da As SqlDataAdapter = New SqlDataAdapter("SELECT MyColumn1, MyColumn2 FROM myTable WHERE mySearchColumn = @SEARCH", con)
da.SelectCommand.Parameters.AddWithValue("@SEARCH", myTextBox.Text)
Dim dt As DataTable = New DataTable()
da.Fill(dt)
myDataGridView.DataSource = dt
End Using
End Using