Error handling ClientContext CSOM SharePoint Online

Question

What is the best way to handle errors for ClientContext is there a reference material for errors thrown. When using the HTTPWebRequest you can check the status ie 403, 500. is there anything similar for the ClientContext.

I would like to implement some kind of retry etc or re authenticate if anything fails

Answer 1

You can follow the normal pattern

try {
    ...
}
catch (Exception) {
    //Get error code and act
}
finally {
    ...
}

Here is a nice blog which explains

1. Problem with this try/catch/finally approach
2. How to use ExceptionHandlingScope?
3. Comparison

Answer 2

For server side exception handling in SharePoint 2010 and onwards you can use an ExceptionHandlingScope to provide server side fallback behaviour.

MSDN has a guide on how to use it which can be found here: https://msdn.microsoft.com/en-us/library/office/ee534976(v=office.14).aspx

To summarize:

• Instantiate an ExceptionHandlingScope object, and within a using scope of it's StartScope method
  • Place your CSOM query within a using scope of StartTry
  • Place your exception handling code within a using scope of StartCatch
  • Place your finalize handling code within a using scope of StartFinally
• Finally, after the StartScope using scope, call ExecuteQuery

e.g.

ClientContext clientContext = new ClientContext("http://MyServer/sites/MySiteCollection");            
ExceptionHandlingScope scope = new ExceptionHandlingScope(clientContext);            
using (scope.StartScope())
{
  using (scope.StartTry())
  {
    // CSOM query code which may fail here
  }
  using (scope.StartCatch())
  {                    
    // CSOM fallback code here          
  }
  using (scope.StartFinally())
  {                    
    // CSOM finally code here                           
  }
}
clientContext.ExecuteQuery();