I'm trying to connect a C# application (using Visual C# 2008 Express Edition) to a remote MySQL server. I have the drivers for this, but when I followed the tutorials (including adding the pooling and connection reset properties), I get an error that: Object reference not set to an instance of an object. I've included the two lines of code that should be making a connection. The error is thrown on the second line.
MySqlConnection connect = new MySqlConnection("database=d*******;Data Source=mysql.netfirms.com;user id=*******;pwd=*****;pooling=false;connection reset=false");
connect.Open();
I'd try setting the connection string outside of the constructor to help narrow down the issue:
MySqlConnection connect = new MySqlConnection();
//Do you get the null exception in this next line?
connect.ConnectionString = "your conn string here";
connect.Open(); //-> If you get the exception here then the problem is with the connection string and not the MySqlConnection constructor.
If you do get the exception in the connect.ConnectionString = ... line, then the problem is with the driver and sounds like you need to reinstall it.
I would also try a simpler connection string, without the pooling and reset keys.
Can you post more code? The exception line is probably a bit off due to compiler optimization or related. Constructors must return an object or throw an exception. It is impossible to say
MyType item = new MyType();
Debug.Fail(item == null); // will never fail.
The null reference is probably on the line just above your instantiation.
可能与此错误有关吗?
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