保存列表中的托管元数据，TaxonomyField 字段类型

        internal const int MAX_LENGTH = 255;
        internal static readonly Regex NameRegex = new Regex("[;<>|\t]", RegexOptions.Compiled | RegexOptions.IgnoreCase);
        internal static readonly Regex SpaceRegex = new Regex("[ ]{2,}", RegexOptions.Compiled | RegexOptions.IgnoreCase);
        private string GetValidTermName(string name)
        {
            if (NameRegex.IsMatch(name))
            {
                name = NameRegex.Replace(name, " ");

            }
            name = SpaceRegex.Replace(name, " ");
            name = name.Length > MAX_LENGTH ? name.Substring(0, MAX_LENGTH) : name;
            name = name.Replace(Convert.ToChar(38), Convert.ToChar(65286));
            return name.Trim();
        }
        private void WriteTagsToFolksonomyColumn(IEnumerable<string> tags, SPListItem item, TaxonomyField column)
        {
            if (!column.IsTermSetValid) return;
            if (!column.Open) return;
            var session = new TaxonomySession(item.Web.Site);
            var mms = session.TermStores[column.SspId];
            var ts = mms.GetTermSet(column.TermSetId);
            if (!ts.IsOpenForTermCreation) return;
            var addedTerms = new List<Term>();
            bool hasChanges = false;
            foreach (var tag in tags)
            {
                if (tag.Length > MAX_LENGTH) continue;
                var validTag = GetValidTermName(tag);
                Term matchingTerm=null;
                if (column.IsKeyword)
                {
                    TermCollection terms = mms.GetTerms(validTag, false, StringMatchOption.ExactMatch, 1, true);
                    if (terms.Count > 0)
                        matchingTerm = terms[0];
                }
                else
                {
                    TermCollection terms = ts.GetTerms(validTag, false, StringMatchOption.ExactMatch, 1, true);
                    if (terms.Count > 0)
                        matchingTerm = terms[0];
                }
                if (matchingTerm == null)
                {
                    matchingTerm = ts.CreateTerm(validTag, mms.WorkingLanguage);
                    hasChanges = true;
                }
                if (!addedTerms.Contains(matchingTerm))
                {
                    addedTerms.Add(matchingTerm);
                }
            }
            if (hasChanges) mms.CommitAll();
            if (addedTerms.Count > 0)
            { 
                if (column.AllowMultipleValues)
                    column.SetFieldValue(item, addedTerms, mms.WorkingLanguage);
                else
                    column.SetFieldValue(item, addedTerms[0]);
            }
        }