GDI+ System.Drawing.Bitmap gives error Parameter is not valid intermittently

Question

I have some C# code in an ASP.Net application that does this:

Bitmap bmp = new Bitmap(1184, 1900);

And occasionally it throws an exception \"Parameter is not val

Answer 1

You not only need enough memory, it needs to be contiguous. Over time memory becomes fragmented and it becomes harder to find big blocks. There aren't a lot of good solutions to this, aside from building up images from smaller bitmaps.

new Bitmap(x, y) pretty much just needs to allocate memory -- assuming that your program isn't corrupted in some way (is there any unsafe code that could corrupt the heap), then I would start with this allocation failing. Needing a contiguous block is how a seemingly small allocation could fail. Fragmentation of the heap is something that is usually solved with a custom allocator -- I don't think this is a good idea in IIS (or possible).

To see what error you get on out of memory, try just allocation a gigantic Bitmap as a test -- see what error it throws.

One strategy I've seen is to pre-allocate some large blocks of memory (in your case Bitmaps) and treat them as a pool (get and return them to the pool). If you only need them for a short period of time, you might be able to get away with just keeping a few in memory and sharing them.