Memory leaks in a Windows Forms application

Question

We are developing a big .NET Windows Forms application. We are facing a memory leak/usage problem in that despite we are disposing the forms.

The scenario is like:

1. Our application is using 60 KB of memory with a list of records displaying in a grid.
2. When the user clicks on a record it opens a form, myform.showDialog, show the details. The memory jumps from 60 KB to 105 MB.
3. Now we close the form myform to get back to grid, and dispose that form and set it to null. Memory remains at 105 MB.
4. Now if we again perform step 2, it would jump from 105 MB to 150 MB and so on.

How can we free up the memory when we close myForm?

We have already tried GC.Collect(), etc., but without any result.

Answer 1

The first place to look for leaks is in event-handling rather than missing Dispose() calls. Say your container (the parent form) loads a child form and adds a handler for an event of that child form (ChildForm.CloseMe).

If the child form is intended to be cleared from memory then this event handler must be removed before it is a candidate for garbage collection.

Answer 2

Disposing the forms is not necessarily a guarantee that you are not leaking memory. For example, if you are binding it to a dataset but you are not disposing of the dataset when you are done, you will probably have a leak. You may need to use a profiling tool to identify which disposable resources are not being released.

And btw, calling GC.Collect() is a bad idea. Just saying.