title: ASP.NET - I am generating an .XLS file with a DLL, how do I grant permissions for writing to file? (IIS 7)
body: <p>I'm generating an .XLS file with a DLL (Excel Library <a href="http://code.google.com/p/excellibrary/" rel="nofollow noreferrer">http://code.google.com/p/excellibrary/</a>)</p>
  
  <p>I've added this DLL as a reference to my project.</p>
  
  <p>The code to save the .XLS to disk is running, but it's encountering a permissions issue. </p>
  
  <p>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. </p>
  
  <p>Here's where I'm trying to write the file:</p>
  
  <pre><code>c:/temp/test1.xls
  </code></pre>
  
  <p>Here's the error:</p>
  
  <pre><code>[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&amp; 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) +11041511
     System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +11041050
     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&amp; completedSynchronously) +171
  </code></pre>
  
  <p>Any idea what I need to do to diagnose the permissions issue and allow the file creation?</p>
  
  <p>Thanks.</p>