private static IEnumerable <IExternalExcelApplicationLoader> GetAssemblyLoaders()
{
ModuleProc PROC = new ModuleProc("", "GetAssemblyLoaders");
IList <IExternalExcelApplicationLoader> loaders = new List <IExternalExcelApplicationLoader>();
try
{
string assemblyNames = Extensions.GetAppSettingValue("ExternalExcelApplicationLoaders", "BMC.ExcelLibrary.dll;ClosedXML.dll");
if (!assemblyNames.IsEmpty())
{
string[] assemblies = assemblyNames.Split(';');
if (assemblies != null)
{
foreach (var assembly in assemblies)
{
string asmPath = Path.Combine(Extensions.GetStartupDirectory(), assembly);
Log.Info(PROC, "Excel Assembly Loader : " + asmPath);
if (File.Exists(asmPath))
{
try
{
Assembly asm = Assembly.LoadFrom(asmPath);
if (asm != null)
{
var loaderType = (from t in asm.GetTypes()
where typeof(IExternalExcelApplicationLoader).IsAssignableFrom(t)
select t).FirstOrDefault();
if (loaderType != null)
{
IExternalExcelApplicationLoader loader = Activator.CreateInstance(loaderType) as IExternalExcelApplicationLoader;
if (loader != null)
{
loaders.Add(loader);
}
}
}
}
catch (Exception ex)
{
Log.Exception(PROC, ex);
}
}
}
}
}
}
catch (Exception ex)
{
Log.Exception(PROC, ex);
}
return(loaders);
}
public static IExternalExcelApplication Create()
{
ModuleProc PROC = new ModuleProc("ExternalExcelLibraryFactory", "Create");
IExternalExcelApplication result = default(IExternalExcelApplication);
try
{
if (_activeLibraryLoader == null)
{
lock (_librariesLock)
{
if (_activeLibraryLoader == null)
{
try
{
IEnumerable <IExternalExcelApplicationLoader> libraryLoaders = null;
try
{
libraryLoaders = MEFHelper.GetExportedValues <IExternalExcelApplicationLoader>();
}
catch
{
libraryLoaders = GetAssemblyLoaders();
}
if (libraryLoaders != null)
{
_libraryLoaders = (from l in libraryLoaders
orderby l.LibraryOrder
select l).ToArray();
if (_libraryLoaders != null)
{
// load the first matched library until find valid one
foreach (IExternalExcelApplicationLoader libraryLoader in _libraryLoaders)
{
if (libraryLoader != null)
{
if (libraryLoader.IsLoadedProperly)
{
Log.Info(PROC, "Excel Library : " + libraryLoader.LibraryName + " (Loaded)");
_activeLibraryLoader = libraryLoader;
break;
}
else
{
Log.Info(PROC, "Excel Library : " + libraryLoader.LibraryName + " (Unable to load)");
}
}
}
}
}
}
catch (Exception ex)
{
Log.Exception(PROC, ex);
}
}
}
}
// still no external loaders found (then take ExcelPackage as a rescuer)
if (_activeLibraryLoader == null)
{
_activeLibraryLoader = new OpenXmlExcelApplicationLoader();
}
if (_activeLibraryLoader != null)
{
IExternalExcelApplication library = null;
try
{
library = _activeLibraryLoader.Create();
}
catch { library = null; }
if (library != null)
{
result = library;
Log.Info(PROC, "Excel Library : " + _activeLibraryLoader.LibraryName + " (Created)");
}
}
}
catch (Exception ex)
{
Log.Exception(PROC, ex);
}
return(result);
}
