//获取到bin目录的下层路径：bin\Debug\
            string aa = System.AppDomain.CurrentDomain.SetupInformation.ApplicationBase;
            string cc = System.AppDomain.CurrentDomain.BaseDirectory;
            
            //获取到bin目录：bin\Debug
            string dd = System.Environment.CurrentDirectory;
            string ee = System.IO.Directory.GetCurrentDirectory();
            string ff = System.Windows.Forms.Application.StartupPath;
 
            //获取程序.exe
            string bb = System.Windows.Forms.Application.ExecutablePath;

------解决方案--------------------
C# code
 string filePath = Application.StartupPath + @"/aaa.xml";

------解决方案--------------------
C# code

XmlDocument mydom = new XmlDocument();                mydom.Load(System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location)+ @"\xxx.xml");