public class OpcDANode
  {
      public bool IsRoot { get; set; } = false;
      public List<OpcDANode> ChildNodes { get; set; } = new List<OpcDANode>();
      public DANodeElement Node { get; set; }
 
      public bool HasChildNodes => ChildNodes.Count > 0;
 
      public string TagNameFull { get; set; }
 
      public string TagNameLastPart => Node?.Name ?? string.Empty;
 
      public bool IsLeaf => Node?.IsLeaf ?? false;
 
      public OpcDANode(DANodeElement node = null)
      {
          Node = node;
          TagNameFull = node?.ItemId ?? string.Empty;
      }
  }
 
   public async Task<List<OpcDANode>> GetAllNodesAsync()
 {
     var rootNode = new OpcDANode
     {
         IsRoot = true,
         TagNameFull = "Root"
     };
 
     try
     {
         BrowseRecursiveNodesPro(rootNode, true);
     }
     catch (Exception ex)
     {
         Log.Error("Error while browsing OPC DA items: {ErrorMessage}", ex.Message);
         throw;  
     }
 
     return new List<OpcDANode>() { rootNode };
 }
 
        private void BrowseRecursiveNodesPro(OpcDANode parentNode, bool isFirstRun = true, bool skipFirstlevelFromTagName = true)
       {
           if (isFirstRun)
           {
               parentNode.IsRoot = true;   
               parentNode.TagNameFull = parentNode.Node?.ItemId ?? "Root";   
           }
 
           var nodeFilter = new DABrowseParameters(); 
           DANodeElementCollection nodeElementCollection = new DANodeElementCollection();
 
           try
           {
               nodeElementCollection = _client.BrowseNodes(Server, isFirstRun ? "" : parentNode.TagNameFull, nodeFilter);
           }
           catch (OpcException oex)
           {
               Log.Logger.Error(oex, $"OPC Exception while browsing nodes at node {parentNode?.TagNameFull ?? "root"}.");
               return;
           }
           catch (Exception ex)
           {
               Log.Logger.Error(ex, $"Error browsing OPC nodes at node {parentNode?.TagNameFull ?? "root"}.");
               return;
           }
 
           foreach (var nodeElement in nodeElementCollection)
           {
               if (nodeElement != null)
               {
                   var childNode = new OpcDANode
                   {
                       Node = nodeElement,
                       IsRoot = false
                   };
 
                   if (isFirstRun)
                   {
                       childNode.TagNameFull = $"{nodeElement.ItemId}";
                   }
                   else
                   {
                       childNode.TagNameFull = $"{parentNode.TagNameFull}.{nodeElement.ItemId}";
                   }
 
                   parentNode.ChildNodes.Add(childNode);
 
                   if (nodeElement.IsBranch && nodeElement.ItemId != "SimulateEvents")
                   {
                       BrowseRecursiveNodesPro(childNode, false);
                   }
               }
           }
       }