a href="https://docs.microsoft.com/dotnet/api/system.string" target="_blank">System<span id="LSTCDFA26B9_2"></span><script type="text/javascript">AddLanguageSpecificTextSet("LSTCDFA26B9_2?cs=.|vb=.|cpp=::|nu=.|fs=.");</script>String</a><br /></dd><dt><span class="parameter">mpnews</span></dt><dd>类型：<a href="T_Senparc_Weixin_Work_AdvancedAPIs_Chat_Chat_MpNews.htm">Senparc.Weixin.Work.AdvancedAPIs.Chat<span id="LSTCDFA26B9_3"></span><script type="text/javascript">AddLanguageSpecificTextSet("LSTCDFA26B9_