Microsoft.VisualStudio.Project.AssemblyReferenceNode.IsAlreadyAdded C# (CSharp) Method

        protected internal override bool IsAlreadyAdded(out ReferenceNode existingReference)
        {
            ReferenceContainerNode referencesFolder = this.ProjectMgr.FindChild(ReferenceContainerNode.ReferencesNodeVirtualName) as ReferenceContainerNode;
            Debug.Assert(referencesFolder != null, "Could not find the References node");
            bool shouldCheckPath = !string.IsNullOrEmpty(this.Url);

            for(HierarchyNode n = referencesFolder.FirstChild; n != null; n = n.NextSibling)
            {
                AssemblyReferenceNode assemblyReferenceNode = n as AssemblyReferenceNode;
                if(null != assemblyReferenceNode)
                {
                    // We will check if the full assemblynames are the same or if the Url of the assemblies is the same.
                    if(String.Compare(assemblyReferenceNode.AssemblyName.FullName, this.assemblyName.FullName, StringComparison.OrdinalIgnoreCase) == 0 ||
                        (shouldCheckPath && NativeMethods.IsSamePath(assemblyReferenceNode.Url, this.Url)))
                    {
                        existingReference = assemblyReferenceNode;
                        return true;
                    }
                }
            }

            existingReference = null;
            return false;
        }