Check if the Item is children of TargetItem

childItem.Axes.IsDescendantOf(parenItem);

Clear Server Cache Inteface

Caching contents to speed up processing of contents can be done on the client machine as well as on the server. There are times things do not go according to what we want it to be because of caching. Fortunately, clearing server cache in Sitecore is not as complicated as I initally thought. To clear server cache go to the Sitecore Clear Cache interface which is 

www.yourwebsite.com/sitecore/admin/cache.aspx.