Originally Posted by
BluePaper 
Through using Visual Studio to learn more about ASP.net and VB.net I would like to connect to a database. I create an .mdf database file but I've no idea how to connect to it (well, I have some code below...) that's not my only problem but I'll ask the next question in a moment. The code I'm using is shown below, am I missing something? Or using the wrong connection string?
Private Function sqlDBConnection() As Boolean
'Set the variables
Dim SQLConnectionString As String
Dim SQLConnection As New SqlConnection()
'Create the Connection String
SQLConnectionString = "Data Source=.\SQLEXPRESS;AttachDbFilename=\App_Data\Overland.mdf;Initial Catalog=Overland;Integrated Security=True;User Instance=True"
'Set the connection string into the SQL connection
SQLConnection.ConnectionString = SQLConnectionString
'Open up the connection
SQLConnection.Open()
End Function
A similar connection string works ( "Data Source=LAMBDA\SQLEXPRESS;Initial Catalog=General;Integrated Security=True" ) with an actual database server (SQL Express 2005) but modifying it a bit doesn't work for an SQL Server file (.mdf in this case) so if you have any idea please help 
Secondly as you can see I've got the function set as a Boolean, however I don't return anything and the .Open() function doesn't return anything. Therefore how can I check to see whether a connection is succesful or not before it breaks out into an error? I'd like to be able to catch it just incase.
Thanks for your time.
You cannot directly 'Open' and .mdf file with Vb.NEt. You need to you an SQL server or MSDE. The second connection string you mention appears to connect to an SQL server, hence why it works.
As to your second question, If you are looking to catch exceptions, use the Try Catch method as demontrated below:
Try
SQLConnection.Open()
Catch Ex As System.Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Error Information")
End Try
If you are looking to obtain the state of an SQL connection before you open it you can use this if statement:
If sqlConnection.State = ConnectionState.Closed Then
sqlConnection.Open()
End If
Hope this helps.
Green2Go
Last edited by green2go : Mar 25th, 2008 at 6:02 pm. Reason: Typo :P
