Do I need to close SQL Server connection with the using keyword?
asp.net, c#, database-connection
Solution
The `using` keyword as used here:
using (SqlConnection cn = new SqlConnection(strConnectString))
{
// Stuff
}
is short for:
SqlConnection cn = null;
try
{
cn = new SqlConnection(strConnectString);
// Stuff
}
finally
{
if (cn != null) cn.Dispose();
}
`cn.Dispose()` will be called immediately after `cn` goes out of scope of the `using`, which in turn immediately closes the connection (because SqlConnection.Dispose() does just that).
UPDATE
This should not be confused with garbage collection. GC is non-deterministic in .NET, which is exactly why the IDisposable inteface and Dispose Pattern were introduced. IDisposable allows expensive resources to be released in a timely, deterministic manner.
Problem
I keep finding conflicting results for this question. Let's look at this C# code of running an SQL query: ``` using (SqlConnection cn = new SqlConnection(strConnectString)) { cn.Open(); using (SqlCommand cmd = new SqlCommand(strSQL, cn)) { cmd.ExecuteNonQuery(); } //Do I need to call? cn.Close(); } ``` Do I need to call that last `cn.Close()`? The reason I'm asking is that in a heavy traffic web app I run out of connections in a pool.