Easy Check If An SPWeb/SPList Exist

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I write a lot of code using the SharePoint object model. Often times, I want to check to see if a particular Web exists in a Site Collection or a List exists in a Web. I used to write methods that enumerated through the collection to see if they existed or I wrapped a Try-Catch block around the code in case the object didn’t exist.

Recently I came across a code snippet that made checking for the existence of a web or list easy. I can’t remember where I found it so I’ll thank the nameless person who originally wrote the code. I’m only capturing it here for my own reference and possibly help someone else.


        static bool ListExists(SPWeb web, string listName)
        {
            return web.Lists.Cast().Any(list => string.Equals(list.Title, listName));
        }


        static bool WebExists(SPSite site, string webName)
        {
            return site.AllWebs.Cast().Any(web => string.Equals(web.Name, webName));
        }

Comments

6 responses to “Easy Check If An SPWeb/SPList Exist”

August 22, 2010

Joen Zhang

We can check if webName is existing SPWebCollection.Names.
So i often use a extension method for SPWebCollection:
public static class SPWebCollectionExtension
{
public static Boolean Contains(this SPWebCollection webCollection, String webName)
{
if (webCollection == null) throw new ArgumentNullException(“webCollection”);
if (String.IsNullOrEmpty(webName)) throw new ArgumentException(“webName”);
return Array.Exists(webCollection.Names, s => s.Equals(webName, StringComparison.CurrentCultureIgnoreCase));
}
}
September 20, 2010

sameer

Nice blog! Thanks for sharing!
October 19, 2010

Sarika

Thanks a lot
May 13, 2011

Simon

These methods are not very efficient if there are a large number of lists/webs, because all of them are iterated.

To check if a list exists, better use the TryGetList() approach:

return web.Lists.TryGetList(listName) != null
May 24, 2011

David Petersen
Thank you everyone for commenting on this post. I want to clarify a few things:

These methods are only available if you reference System.Linq which is in .NET Framework 3.5. (Target framework: .NET Framework 3.5 from the Application, Project Properties).

As long as you are targeting .NET Framework 3.5 in your project, you can use these methods on WSS 3.0 based projects.

The way the lambda works is that is will iterate through the list until it finds a match or reaches the end. This is not the most efficient way but with WSS 3.0, it is the cleanest way (IMHO) outside of trapping an error in a TryCatch block.

The TryGetList() method is only available in SharePoint 2010.

Keep the comments coming. I learn something new everyday!
July 28, 2011

Easy Check If An SPWeb/SPList Exist | Hexanes!

[…] great post, one of those finer details of SharePoint API development that I use a lot as well: Easy Check If An SPWeb/SPList Exist By David Petersen, January 20, 2010 2:57 […]