.net - Systerm.Configuration.ConfigurationSettings does not contain a definition for appSettings -

i new programming, trying copy files 1 location another, trying use app.config file in visual studio 2010.

the config file

<?xml version="1.0" encoding="utf-8" ?> <configuration> <appsettings> <add key="sourcepath" value="c:\users\public\testfolder"/> <add key="targetpath" value="c:\users\public\testfolder\subdir"/> </appsettings> </configuration> 

the code copy file is

using system; using system.collections.generic; using system.linq; using system.text;  namespace filecopy {     class filecopy     {         class simplefilecopy         {             static void main()             {                 string filename = "test.txt";                 string sourcepath = system.configuration.configurationsettings.appsettings["sourcepath"];                 string targetpath = system.configuration.configurationsettings.appsettings["targetpath"];                  // use path class manipulate file , directory paths.                 string sourcefile = system.io.path.combine(sourcepath, filename);                 string destfile = system.io.path.combine(targetpath, filename);                  // copy folder's contents new location:                 // create new target folder, if necessary.                 if (!system.io.directory.exists(targetpath))                 {                     system.io.directory.createdirectory(targetpath);                 }                  // copy file location ,                  // overwrite destination file if exists.                 system.io.file.copy(sourcefile, destfile, true);                  // copy files in 1 directory directory.                 // files in source folder. (to recursively iterate through                 // subfolders under current directory, see                 // "how to: iterate through directory tree.")                 // note: check target path performed                //       in code example.                 if (system.io.directory.exists(sourcepath))                 {                     string[] files = system.io.directory.getfiles(sourcepath);                      // copy files , overwrite destination files if  exist.                     foreach (string s in files)                     {                         // use static path methods extract file name path.                         filename = system.io.path.getfilename(s);                         destfile = system.io.path.combine(targetpath, filename);                         system.io.file.copy(s, destfile, true);                     }                 }                 else                 {                     console.writeline("source path not exist!");                 }                  // keep console window open in debug mode.                 console.writeline("press key exit.");                 console.readkey();              }         }     } } 

i error when build solution says 'system.configuration.configurationsettings' not contain definition 'appsettings'

what doing wrong? help.

you need use configuration manager:

system.configuration.configurationmanager.appsettings["sourcepath"]