CODEWITHSUNDEEP
vb.netgarbage-collectionidisposable
surpavan
surpavan

Reputation: 1422

IDispose is neccessary, does Garbage collector work at end of loops etc

My question is about IDisposable implementation. To my knowledge, when a code or section is complete, the variable or instance is disposed; please correct me if the statement is wrong. The follow is part of my program:

 If Con.State = ConnectionState.Closed Then Con.Open()
        Cmd = New SqlCeCommand("Select * from BillItem", Con)
        Rdr = Cmd.ExecuteReader()
        While Rdr.Read = True
            Dim x As New Classes.StockRoster
            x.BillID = Rdr("BillID")
            x.IsSales = Rdr("IsSales")
            x.Quantity = Rdr("Quantity")
            x.ContactBase = (From t As CommonCodes.ItemBase In ContactsbaseDict Where t.ID = BillContactDict(x.BillID)).First
            x.StockEntityBase = StockEntitydict(Rdr("StockID"))
            x.BillDate = Rdr("BillDate")
            result.AddRange(x)
        End While
        Con.Close()
 End IF

In case of X variable here, would there be any memory improvement if I x (or StockRoster) would use IDisposable interface?

Couldn't the resources get disposed by default at end of each loop?

Upvotes: 0

Views: 137

Answers (2)

Tim Schmelter
Tim Schmelter

Reputation: 460278

First, you would never enter the If-clause if the connection is open what could happen f.e. in case of an exception.

Actually the connection is the best example. Always close connections as soon as possible. The easiest way is to use using-statement which calls Dispose at the end (even in case of an exception). So it's similar to a Try/Catch/Finally. Connection.Dispose will also close it implicitely.

As a rule of thumb: use the using-statement for anything implementing IDisposable (like the SqlCeCommand above).

To answer you actual question:

would there be any memory improvement if I x (or StockRoster) would use IDispose class, couldn't the resources get dispose by default at end of each loop?

What is memory improvement, IDisposable is an interface, you could call dispose or close even when the class doesn't implement IDisposable. That's just a hint that it probably uses unmanaged resources and should be disposed as soon as possible.

Upvotes: 1

Meta-Knight
Meta-Knight

Reputation: 17875

IDisposable is about disposing unmanaged resources such as a database connection. It doesn't have anything to do with the garbage collection.

Your StockRoster class doesn't seem to hold unmanaged resources so it doesn't need to implement IDisposable. Even if it did, it wouldn't make sense to dispose it in your for loop, because you add the instance to the result list that you will later use. Disposing it in the for loop would make the instance unusable in the calling code.

Upvotes: 1

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