Question

I’m generating an .XLS file with a DLL (Excel Library http://code.google.com/p/excellibrary/)

I’ve added this DLL as a reference to my project.

The code to save the .XLS to disk is running, but it’s encountering a permissions issue.

I’ve attempted to set full access for IUSRS, Network Service, and Everyone just to see if I could get it working, and none of these seems to make a difference.

Here’s where I’m trying to write the file:

c:/temp/test1.xls

Here’s the error:

[SecurityException: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.]
   System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet) +0
   System.Security.CodeAccessPermission.Demand() +54
   System.IO.FileStream.Init(String path, FileMode mode, FileAccess access, Int32 rights, Boolean useRights, FileShare share, Int32 bufferSize, FileOptions options, SECURITY_ATTRIBUTES secAttrs, String msgPath, Boolean bFromProxy) +2103
   System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share, Int32 bufferSize, FileOptions options, String msgPath, Boolean bFromProxy) +138
   System.IO.FileStream..ctor(String path, FileMode mode, FileAccess access, FileShare share) +89
   System.IO.File.Open(String path, FileMode mode, FileAccess access, FileShare share) +58
   ExcelLibrary.Office.CompoundDocumentFormat.CompoundDocument.Create(String file) +88
   ExcelLibrary.Office.Excel.Workbook.Save(String file) +73
   CHC_Reports.LitAnalysis.CreateSpreadSheet_Click(Object sender, EventArgs e) in C:\Users\brian\Desktop\Enterprise Manager\CHC_Reports\LitAnalysis.aspx.vb:19
   System.Web.UI.WebControls.Button.OnClick(EventArgs e) +115
   System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +140
   System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +29
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) [phone]
   System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) [phone]
   System.Web.UI.Page.ProcessRequest() +91
   System.Web.UI.Page.ProcessRequest(HttpContext context) +240
   ASP.litanalysis_aspx.ProcessRequest(HttpContext context) +52
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +599
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +171

Any idea what I need to do to diagnose the permissions issue and allow the file creation?

Thanks.

Answer 1

I believe that Nelson was on the right track for 90% of people that run into this error… and I believe that tgolisch was on the right track for about 8% of the remaining.

However, the application pool that was serving up my application apparently did not have specific rights to write to the folders in question. Therefore, I switched the application pool being used to serve up the application to run under the context: Local System.

When I deploy the application, I will need to determine which identity the application pool is running under and verify that it has access to the appropriate folders.