ADODB.Stream instead of Scripting.FileSystemObject.
In a Silverlight 4 OOB App (even with elevated trust), you cannot access files in locations outside of 'MyDocuments' and a couple of other user related special folders. You have to use the workaround 'COM+ Automation'. But the Scripting.FileSystemObject, which works great for text files, cannot handle binary files. Fortunately you can also use ADODB.Stream there. And that handles binary files just fine. Here is my code, tested with Word Templates, .dotx files:
public static void WriteBinaryFile(string fileName, byte[] binary){ const int adTypeBinary = 1; const int adSaveCreateOverWrite = 2; using (dynamic adoCom = AutomationFactory.CreateObject("ADODB.Stream")) { adoCom.Type = adTypeBinary; adoCom.Open(); adoCom.Write(binary); adoCom.SaveToFile(fileName, adSaveCreateOverWrite); }}?A file read can be done like this:
public static byte[] ReadBinaryFile(string fileName){ const int adTypeBinary = 1; using (dynamic adoCom = AutomationFactory.CreateObject("ADODB.Stream")) { adoCom.Type = adTypeBinary; adoCom.Open(); adoCom.LoadFromFile(fileName); return adoCom.Read(); }}?