DataRow[] rows = dataRow.GetChildRows("TreeRelation");

https://docs.microsoft.com/zh-cn/dotnet/api/system.data.datarow.getchildrows?redirectedfrom=MSDN&view=net-5.0#System_Data_DataRow_GetChildRows_System_String_

http://blog.sina.com.cn/s/blog_507668a00100a4yf.html

ConfigurationManager类

https://docs.microsoft.com/zh-cn/dotnet/api/system.configuration.configurationmanager?redirectedfrom=MSDN&view=dotnet-plat-ext-5.0