Hello I have some trouble with my coding due the changes in codes from Kentico 5.5 to 7.
It's been 2 days try to figure out the errors but I didn't found the solution.

First error:

I get Error Cannot implicitly convert type 'CMS.DocumentEngine.TreeNodeDataSet' to 'System.Data.DataSet'. And 'CMS.DocumentEngine.TreeNode' does not contain a constructor that takes 3 arguments

The code for this part is

  public static void AddInDocsAndFields(Dictionary<string, List<string>> docsAndFields, List<string> keywordsList)
        {
            foreach (KeyValuePair<string, List<string>> pair in docsAndFields)
            {
                string key = pair.Key;
                List<string> columns = pair.Value;
                TreeProvider provider = new TreeProvider(CMSContext.CurrentUser);
                DataSet set = provider.SelectNodes(CMSContext.CurrentSiteName, null, CMSContext.CurrentUser.PreferredCultureCode, false, key);
                if (((set != null) && (set.Tables.Count != 0)) && (set.Tables[0].Rows.Count != 0))
                {
                    for (int i = 0; i < set.Tables[0].Rows.Count; i++)
                    {
                        TreeNode node = new TreeNode(set.Tables[0].Rows, key, provider);
                        AddInFields(node, columns, keywordsList);
                    }
                }
            }
        }

Second major error I get:

get_DataRow, I tried to found something similar but no success

   if (node2..Table.Columns.Contains(columns[j]))
                    {
                        string columnHtml = node2.get_DataRow()[columns[j]] as string;
                        list2 = GetJustNeededKeywords(columnHtml, node2.get_DocumentID().ToString(), keywordsAndUrlDocIds);
                        if ((list2 != null) && (list2.Count != 0))
                        {
                            str2 = replacer.ChangeKeywordsSgml(columnHtml, list2);
                            if (columnHtml != str2)
                            {
                                node2.SetValue(columns[j], str2);
                                flag = true;
                            }

Thank you for your time