Close a thread against a mysql database in c#

Question

What is the proper way of closing a tread after running a query against a MySql database from a windows form in C#?

Is a simple open close enough like this?

conn.Open();

//querycode

conn.Close():

What do you mean by "close a tread"? Do you mean you want to make sure that the connection is closed after making a SQL call? — Mark Carpenter, Oct 08 '09 at 18:27
the problem im getting is that when i use the tool iv created m somtimes getting the "Too many connections" error, my mysql database is set ut with max_connections 100. and when i run a simple conn.Close(); after each query it does not seem to close the connection to the db. it dont releases the MySql treads before i restart the SW. — Darkmage, Oct 08 '09 at 18:35

score 3 · Accepted Answer · answered Oct 08 '09 at 18:27

3

Try to use:

using(MySqlConnection conn = new MySqlConnection(connString))
{
    conn.Open();
} // conn is automatically closed and disposed at the end of the using block

answered Oct 08 '09 at 18:27

Justin Niessner

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csl · Answer 2 · 2009-10-08T18:39:14.237

Classes that use resources that you need to clean up afterwards usually implement the IDisposable interface. This means it provides a function called Dispose() that can be used to free resources.

For disposable objects, you can use the using statement:

using ( SomeDisposableClass c = new SomeDisposableClass() ) {

    // ... your code here

} // c.Dispose() automatically called here, freeing up resources

If the class is properly coded, it should free any resources -- be it a database connection, an opened file handle, etc -- in its Dispose() function.

This means that the MySQL probably disconnects from the database in Dispose(), so you probably don't need to explicitly call c.Close() -- but always check the documentation to be sure.

score 0 · Answer 3 · edited May 23 '17 at 11:55

0

it is okay the way you are doing it, you can also wrap connection object into using block like this:

using (var con = new MySqlConnection(/*connection string*/))
{
    con.Open();
    //do stuff
    // con.Close(); //don't need this it will be closed automatically* 
}

(*see)

edited May 23 '17 at 11:55

Community

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answered Oct 08 '09 at 18:27

TheVillageIdiot

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1

con.Close(); is redundant here. – Joel Coehoorn Oct 08 '09 at 18:30
for me it dont seem redundant because my app seems ot build more and more treads as im browing the MySql db from my tool. – Darkmage Oct 08 '09 at 18:38

score 0 · Answer 4 · answered Oct 08 '09 at 18:32

No, the code in your question is not good enough. If your query throws an exception you won't Close() it in a timely manner and it will be left hanging until the garbage collector notices it.

You need to enclose the object in a using block as shown by others or at a bare minimum encase it in a try/finally structure.

Close a thread against a mysql database in c#

4 Answers4