How do I test if I will be able to execute a query (does the site exist)

Question

When I run a (CAML based query) executeQuery against Sharepoint, sometimes the site does not exist (it is created by a workflow process which may not have run). When this happens, I get a ClientRequestException:

Cannot contact site at the specified URL http:/[mypath]. There is no Web named "/[mypath]/_vti_bin/sites.asmx".

Is there a check I can run? I think it's probably preferable to do a bool check than to wrap with a try catch.

This code runs client side, so I believe there is a different set of APIs available.

Answer 1

I think, the solution here is to use the scopes approach.

There are two scope types in SharePoint: ConditionalScope and ExceptionHandlingScope. They allow you to implement conditional behaivour server-side. Only one request is sent to the server. Logics in scopes are packed together and sent to the server which is executed as a whole in a single request.

The easest way here is to implement server-side try-catch behaivour, using ExceptionHandlingScope, for example:

        ClientContext clientContext = new ClientContext("http://localhost");

        ExceptionHandlingScope scope = new ExceptionHandlingScope(clientContext);

        using (scope.StartScope())
        {
            using (scope.StartTry())
            {
                // do your actions here
            }

            using (scope.StartCatch())
            {
                // if error is occured...
            }
        }

        clientContext.ExecuteQuery();

As far as I know, there are no analogues for SPWeb.Exists in client object model, so using ExceptionHandlingScope is probably the best solution here.

Some articles, which can help to understand server-scopes idea:

1. How to: Use Conditional Scope
2. How to: Use ExceptionHandlingScope

Answer 2

If you are writing code always use this boolean check: SPSite.Exists()

http://msdn.microsoft.com/en-us/library/microsoft.sharepoint.spsite.exists.aspx