Problem when SqlConnection.Open()

hoetat · October 17th, 2007, 12:02 AM

When I try to open a connection to the database I hit an error
"Object reference not set to an instance of an object."

I have make a simple test connection function same error coming out when open connection as the line in red. Here my function:

Code:

private void butConnect_Click(object sender, System.EventArgs e)
{
    SqlConnection connect = null;
    try
    {
        connect = new SqlConnection();
        connect.ConnectionString = "Data Source=(local);Initial Catalog=DB;User ID=sa;Password=password";

        connect.Open();
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

My program is in .NET 1.1. Dunno why the error occur, it work fine previously. Thank you for someone help.

gunjan.sh · October 17th, 2007, 01:08 AM

Try by giving an if condition to test the connection's state....

Code:

private void butConnect_Click(object sender, System.EventArgs e) {
    SqlConnection connect = null;
    try
    {
        connect = new SqlConnection();
        connect.ConnectionString = "Data Source=(local);Initial Catalog=DB;User ID=sa;Password=password";
if(connect.Connectionstate == Connectionstate.Close)
        connect.Open();
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

Gunjan

joefawcett · October 17th, 2007, 02:18 AM

If connect is not set to an instance then testing its state won't work either. The error message you're getting doesn't seem possible with the code you have shown, are you sure you haven't misssed anything out?

--

Joe (Microsoft MVP - XML)

hoetat · October 17th, 2007, 01:02 PM

Really that happen. You can remote into my pc and see the problem.

Regarding the State, my original code is doing that by checking the Close state. Because of the connection is closed so when come to the connect.Open(), it return exception.

joefawcett · October 18th, 2007, 02:38 AM

Okay, how about you zip the project and email it to me? You can remove any passwords from the connection string as I'll use my own database. All I'm saying is that if connect was not set to an instance then the code would fail when you tried to set the ConnectionString property, not on the line you show.

--

Joe (Microsoft MVP - XML)

hoetat · October 19th, 2007, 01:11 PM

Hi Joe, I dont mind to send you the code, actually it just as simple as I show you on this topic, just the few lines.

Since the problem still there, I had reinstall my .NET Framework 1.1 and test the program connection again, it work.
Anyway dunno why after test few times the connection throw the "Object reference..." error again.

Then I reinstall framework 1.1 again, it works again. SIGH...

As a result, I think I will need to hardworking on reinstall framework 1.1 if error occur again.......:(

zawmn83 · June 27th, 2008, 12:36 AM

I also get the same error.
Please check

http://forums.msdn.microsoft.com/de-...-3deeac83e7e8/

jotego · July 6th, 2008, 07:43 PM

It seems to me that your connection string must be wrong. Can you connect to the database with that string using Access for instance?