The BCL System.IO.Packaging uses IsolatedFileStorage when the zipped XLSX file exceeds some specific boundary (I've heard different stories of 1.3MB, 7MB, and 10MB). This presents a variety of issues when running under IIS, whether running under NetworkService or AppPoolIdentity. It's also not thread-safe.
I strongly recommend implementing an alternative packager using a compatible open-source ZIP library such as SharpZipLib or DotNetZip, otherwise people trying to use this to create sizable Excel files server-side are going to have numerous problems, as I've had recently.
As an aside, I'm currently trying out setting the legacyCasMode to True for my IIS application as a workaround, but I don't know yet if this has any effect. It's certainly not ideal.
Comments: HI Rechard/Jan, First of all thanks for your kind help all the time. I would like to know that is the mentioned problem is resolved? I saw it is marked as fixed by Jan. Which version of the EPPLUS contains the fix? I am going through the similer kind of problem. Please suggest if you have any work around avaialble for a quick fix. Thanks.
I strongly recommend implementing an alternative packager using a compatible open-source ZIP library such as SharpZipLib or DotNetZip, otherwise people trying to use this to create sizable Excel files server-side are going to have numerous problems, as I've had recently.
As an aside, I'm currently trying out setting the legacyCasMode to True for my IIS application as a workaround, but I don't know yet if this has any effect. It's certainly not ideal.
Comments: HI Rechard/Jan, First of all thanks for your kind help all the time. I would like to know that is the mentioned problem is resolved? I saw it is marked as fixed by Jan. Which version of the EPPLUS contains the fix? I am going through the similer kind of problem. Please suggest if you have any work around avaialble for a quick fix. Thanks.