RPC error 1702 when calling a WinAPI method from a batch job

You probably already noticed that error messages are sometimes not really helpful when you are trying to understand a problem. The following code creates such misleading error message:

   1:  public void run()
   2:  {
   3:  ;
   4:  if(WinApi::folderExists(@"c:\temp\"))
   5:      info("Folder exists");
   6:  else
   7:      info("Folder does not exists");
   8:  }

If you do execute this code in a batch job, it will produce the following error message:

RPC error: RPC exception 1702 occurred in session xxx

1702 means:

The binding handle is invalid.

A complete list of RPC errors is available here.

But this error message has, of course, nothing to do with the real cause of the problem. The RPC 1702 is unfortunately in Ax 2009 (RTM and SP1) always thrown when you call a client method from a batch job. If you have a look at the code of the WinApi::folderExists(str filename):

   1:  client static boolean folderExists(Filename _filename)
   2:  {
   3:      boolean ret;
   4:      ;
   5:      ret = System.IO.Directory::Exists(_filename);
   6:      return ret;
   7:  }

you see that this method can’t be executed on the AOS because of the “client” keyword. It’s true that this should not work and create an error message (since batch jobs are executed on the AOS), but it should normally be a meaningful message.

Instead of calling this client method, you should change your code, so that this call can be executed on the server. For example like this:

   1:  public void run()
   2:  {
   3:      InteropPermission   interopPerm;
   4:      boolean isFolderExist;
   5:      ;
   7:      interopPerm = new InteropPermission(InteropKind::ClrInterop);
   8:      interopPerm.assert();
   9:      isFolderExist = System.IO.Directory::Exists(@"c:\temp\");
  11:      if(isFolderExist)
  12:      {
  13:          info("Folder exists");
  14:      }
  15:      else
  16:      {
  17:          info("Folder does not exists");
  18:      }
  20:      CodeAccessPermission::revertAssert();
  21:  }
Update (17/07/2009):
You can find a blog entry from Klaas about this subject here:
Comments (4)

  1. You probably already noticed that error messages are sometimes not really helpful when you are trying

  2. Hi Florian,

    The error message is indeed misleading, but the problem is obvious when you know a static method can’t run in batch. Thanks for the explanation, I was struggling with that RPC error.

    There is also a WinApiServer class that contains a lot of the methods that winapi offers. Because all static methods in that class run on server, it works perfectly in batch.

    Some methods that WinApi offers are not found in WinApiServer, but you can extend WinApiServer by copying methods from WinApi and changing ‘client’ to ‘server’. You just have to make sure that you assert the correct permissions (FileIOPermissen, InteropPermission,…) after declaring variables and right before initialising them. Or you can write your own method using System.IO like you did.

    Thank you for helping out!

  3. Jack says:


    Thanks for the explanation! It helps me solve my problem with the batch job.

    I was clueless when batch job didn’t execute and 1702 error was looged on the server – which is actually not an error, but Information (very misleading). It happened after I amended the logic of the process and accidentially include some client static method in it.

    I just wanted to add that in RTM (not sure about SP1) scheduled batch job don’t execute at all, so you’re unable to see any signs of error in AX.

    Thanks again!


  4. Fabio says:

    Hello there!

    I was tried connect web services. I put into .dll in AX Server’s folder. Now, solve my problem.

    bye. Thank you for post guys.