There is not any predefined method to check if any list is exist in SharePoint site but some people find out very good workaround for this. Please go through below article to check list exist or not. Checking whether SPList Exists On basis of this you can add webpart programatically to the page. w: http://www.worldofsharepoint.com | t: @sharesandip

I have created web part which is working fine. Now requirement is there that it should get added to page only and only if particular list is there. Is there any way so that I can check the list before adding to page? and if it is not there display the message to user.