如何動態(tài)修改winform的app.config的鍵值

      如何修改app.config 文件呢，用ConfigurationSettings.AppSettings.Set 方式程序會報錯，在網上找到一段動態(tài)修改winform app.config的代碼，大家分享一下：

  public static void UpdateConfig(string p_strKey, string p_strValue)
  {
   try
   {
    string m_strFullPath = "";
   // Assembly Asm = Assembly.GetExecutingAssembly();
    XmlDocument xmlDoc =new XmlDocument();
    m_strFullPath = System.Windows.Forms.Application.ExecutablePath + ".config";
    xmlDoc.Load(m_strFullPath);
    XmlNodeList nodeList=xmlDoc.SelectSingleNode("/configuration/appSettings").ChildNodes;
    foreach(XmlNode xn in nodeList
    {
     XmlElement xe=(XmlElement)xn;

     if( xe.GetAttribute("key").IndexOf(p_strKey) != -1 )
     {
      xe.SetAttribute("value",p_strValue);
     }
    }
    xmlDoc.Save(m_strFullPath);
   }
   catch(System.NullReferenceException NullEx)
   {
    throw NullEx;
   }
   catch(Exception ex)
   {
    throw ex;
   }
  }