Question

The problem

When I try to save a file over ~1.5 MiB with EPPlus ExcelPackage.Save() throws a System.IO.IsolatedStorage.IsolatedStorageException.

The explanation

I’m creating a SSIS package with Visual Studio 2008 9.0.30729.4462 QFE and .NET Framework 3.5 SP1 to export the content of a SQL Server 2008 SP2 10.0.4311.0 64 bit table through the EPPlus 2.9.0.1 library.

The SSIS package is really simple: an Execute SQL Task which reads the table’s content and puts it in a variable followed by a Script task which reads the recordset variable and saves the content to disk through EPPlus.

The code of the Script Task is:

namespace ST_00a0b40814db4c7290b71f20a45b62c6.csproj
{
    using System;
    using System.AddIn;
    using System.Data;
    using System.Data.OleDb;
    using System.IO;
    using Microsoft.SqlServer.Dts.Runtime;
    using Microsoft.SqlServer.Dts.Tasks.ScriptTask;
    using OfficeOpenXml;

    [AddIn("ScriptMain", Version = "1.0", Publisher = "", Description = "")]
    public partial class ScriptMain : VSTARTScriptObjectModelBase
    {
        public void Main()
        {
            DataTable documentList = new DataTable();
            using (OleDbDataAdapter adapter = new OleDbDataAdapter())
            {
                adapter.Fill(documentList, this.Dts.Variables["DocumentList"].Value);
            }
            if (documentList.Rows.Count > 0)
            {
                FileInfo fileInfo = new FileInfo(@"C:\Temp\Test.xlsx");
                if (fileInfo.Exists)
                {
                    fileInfo.Delete();
                }
                using (ExcelPackage package = new ExcelPackage(fileInfo))
                {
                    ExcelWorksheet worksheet = package.Workbook.Worksheets.Add("Documents");
                    for (Int32 i = 0; i < documentList.Rows.Count; i++)
                    {
                        for (Int32 j = 0; j < documentList.Columns.Count; j++)
                        {
                            worksheet.Cells[i + 1, j + 1].Value = documentList.Rows[i][j];
                        }
                    }
                    package.Save();
                }
            }
            Dts.TaskResult = Convert.ToInt32(DTSExecResult.Success);
        }
    }
}

When I feed the Script Task only a couple of records the package runs fine, but when I run it against the full table the package.Save(); blows up with a System.IO.IsolatedStorage.IsolatedStorageException: Unable to determine the identity of domain exception.

Here you can see the full stack trace:

Error: System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. ---> System.InvalidOperationException: Error saving file C:\Temp\Test.xls ---> System.IO.IsolatedStorage.IsolatedStorageException: Unable to determine the identity of domain.
   at System.IO.IsolatedStorage.IsolatedStorage._GetAccountingInfo(Evidence evidence, Type evidenceType, IsolatedStorageScope fAssmDomApp, Object& oNormalized)
   at System.IO.IsolatedStorage.IsolatedStorage.GetAccountingInfo(Evidence evidence, Type evidenceType, IsolatedStorageScope fAssmDomApp, String& typeName, String& instanceName)
   at System.IO.IsolatedStorage.IsolatedStorage._InitStore(IsolatedStorageScope scope, Evidence domainEv, Type domainEvidenceType, Evidence assemEv, Type assemblyEvidenceType, Evidence appEv, Type appEvidenceType)
   at System.IO.IsolatedStorage.IsolatedStorage.InitStore(IsolatedStorageScope scope, Type domainEvidenceType, Type assemblyEvidenceType)
   at System.IO.IsolatedStorage.IsolatedStorageFile.GetStore(IsolatedStorageScope scope, Type domainEvidenceType, Type assemblyEvidenceType)
   at System.IO.IsolatedStorage.IsolatedStorageFile.GetUserStoreForDomain()
   at MS.Internal.IO.Packaging.PackagingUtilities.ReliableIsolatedStorageFileFolder.GetCurrentStore()
   at MS.Internal.IO.Packaging.PackagingUtilities.ReliableIsolatedStorageFileFolder..ctor()
   at MS.Internal.IO.Packaging.PackagingUtilities.GetDefaultIsolatedStorageFile()
   at MS.Internal.IO.Packaging.PackagingUtilities.CreateUserScopedIsolatedStorageFileStreamWithRandomName(Int32 retryCount, String& fileName)
   at MS.Internal.IO.Packaging.SparseMemoryStream.EnsureIsolatedStoreStream()
   at MS.Internal.IO.Packaging.SparseMemoryStream.SwitchModeIfNecessary()
   at MS.Internal.IO.Packaging.SparseMemoryStream.Write(Byte[] buffer, Int32 offset, Int32 count)
   at MS.Internal.IO.Packaging.CompressEmulationStream.Write(Byte[] buffer, Int32 offset, Int32 count)
   at MS.Internal.IO.Packaging.CompressStream.Write(Byte[] buffer, Int32 offset, Int32 count)
   at MS.Internal.IO.Zip.ProgressiveCrcCalculatingStream.Write(Byte[] buffer, Int32 offset, Int32 count)
   at MS.Internal.IO.Zip.ZipIOModeEnforcingStream.Write(Byte[] buffer, Int32 offset, Int32 count)
   at System.IO.StreamWriter.Flush(Boolean flushStream, Boolean flushEncoder)
   at System.IO.StreamWriter.Write(String value)
   at System.IO.TextWriter.Write(String format, Object arg0, Object arg1)
   at OfficeOpenXml.ExcelWorksheet.UpdateRowCellData(StreamWriter sw)
   at OfficeOpenXml.ExcelWorksheet.SaveXml()
   at OfficeOpenXml.ExcelWorksheet.Save()
   at OfficeOpenXml.ExcelWorkbook.Save()
   at OfficeOpenXml.ExcelPackage.Save()
   --- End of inner exception stack trace ---
   at OfficeOpenXml.ExcelPackage.Save()
   at ST_00a0b40814db4c7290b71f20a45b62c6.csproj.ScriptMain.Main() in C:\Temp\ScriptMain.cs:line 39
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle._InvokeMethodFast(Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
   at System.RuntimeMethodHandle.InvokeMethodFast(Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeTypeHandle typeOwner)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
   at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.RuntimeType.InvokeMember(String name, BindingFlags bindingFlags, Binder binder, Object target, Object[] providedArgs, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParams)
   at System.Type.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args, CultureInfo culture)
   at Microsoft.SqlServer.Dts.Tasks.ScriptTask.VSTATaskScriptingEngine.ExecuteScript()

I’ve been able to pinpoint the issue to the size of the generated file: when the size of the Excel file grows about 1.5 MiB (this is a more or less value, I’ve not been able to find the exact size), the error shows up.

The only information I’ve been able to find on the net is a blog post, there the blogger proposes a solution where he “outsources” the code to a DLL and uploads it to the server’s GAC and then runs the following code:

AppDomainSetup setup = new AppDomainSetup();
setup.ApplicationBase = rootPath;
setup.DisallowBindingRedirects = false;
setup.DisallowCodeDownload = true;
setup.ConfigurationFile = AppDomain.CurrentDomain.SetupInformation.ConfigurationFile;

Evidence evidence = new Evidence();
evidence.AddHost(new Zone(SecurityZone.MyComputer));

AppDomain ad = AppDomain.CreateDomain("NewAppDomain", evidence, setup);

YourClass yourClass = (YourClass)ad.CreateInstanceAndUnwrap(typeof(YourClass).Assembly.FullName, typeof(YourClass).FullName);

yourClass.aMethod();

AppDomain.Unload(ad);

However, I can’t try this solution because I have no access to the server’s GAC and I can’t have the DLL uploaded.

Is there some other way to bypass this issue?

I also opened a bug report on EPPlus’ issue tracker on the matter.

The summary

• SSIS package
• Visual Studio 2008 9.0.30729.4462 QFE
• .NET Framework 3.5 SP
• SQL Server 2008 SP2 10.0.4311.0 64 bit
• EPPlus 2.9.0.1
• Big output file
• System.IO.IsolatedStorage.IsolatedStorageException: Unable to determine the identity of domain

Answer 1

It turns out that you don’t need to create an entirely new DLL and upload it to the GAC to get this to work. You can just create a new instance of your original class (or a new class with the methods you need to call) in a different AppDomain.

1) Take the code that causes the exception and place it in a seperate method. Make sure that all objects that will be passed in or out are either Serializable or extend MarshalByRefObject. In your case:

public void SavePackage(FileInfo fileInfo, DataTable documentList)
{
    using (ExcelPackage package = new ExcelPackage(fileInfo))
    {
        ExcelWorksheet worksheet = package.Workbook.Worksheets.Add("Documents");
        for (Int32 i = 0; i < documentList.Rows.Count; i++)
        {
            for (Int32 j = 0; j < documentList.Columns.Count; j++)
            {
                worksheet.Cells[i + 1, j + 1].Value = documentList.Rows[i][j];
            }
        }
        package.Save();
    } 
}

2) Create a new instance of your class using the code you mentioned above.

AppDomainSetup setup = new AppDomainSetup();
setup.ApplicationBase = AppDomain.CurrentDomain.BaseDirectory;

Evidence evidence = new Evidence(AppDomain.CurrentDomain.Evidence);
evidence.AddAssembly(Assembly.GetExecutingAssembly().FullName);
evidence.AddHost(new Zone(SecurityZone.MyComputer));

AppDomain ad = AppDomain.CreateDomain(DomainName, evidence, setup);
ScriptMain mainClass = (ScriptMain)ad.CreateInstanceAndUnwrap(typeof(ScriptMain).Assembly.FullName, typeof(ScriptMain).FullName);      

3) Call the method, then unload the AppDomain.

try
{
    mainClass.SavePackage(fileInfo, documentList);
}
finally
{
    AppDomain.Unload(ad);  
}