[.NET][Winform, Console]即時更新app.config的設定(FileSystemWatcher)
當winform or console程式的.exe執行中的時候，有時候總是希望可以改一下app.config的設定，並且不想去關閉.exe並重新啟動
只要利用FileSystemWatcher類別就能達成這個機制囉：
step1:在form_load或是程式剛開始執行的時候，加入FileSystemWatcher的監控
Step2:定義OnChanged()函數
private void ResultForm_Load(object sender, EventArgs e)
{
string yourParam = "";
yourParam = ConfigurationManager.AppSettings["yourKey"];//初始化讀取appsettings的參數
private FileSystemWatcher watcher;
string assemblyDirectory = AppDomain.CurrentDomain.SetupInformation.ApplicationBase;
NotifyFilters notifyFilters = NotifyFilters.LastWrite;
string filter = "*.config";
watcher = new FileSystemWatcher() { Path = assemblyDirectory, NotifyFilter = notifyFilters, Filter = filter };
//當檔案變更的時候，觸發OnChanged()事件
watcher.Changed += OnChanged;
watcher.EnableRaisingEvents = true;
}
//定義OnChanged()事件
private void OnChanged(object source, FileSystemEventArgs e)
{
try
{
//暫時將FileSystemWatcher的觸發事件關閉，趁此時更新app.config設定
watcher.EnableRaisingEvents = false;
//重新從app.config檔案讀取appSettings區塊的設定
ConfigurationManager.RefreshSection("appSettings");
yourParam = ConfigurationManager.AppSettings["yourKey"];//再次讀取appsettings的參數
}
finally
{
watcher.EnableRaisingEvents = true;//更新完畢yourParam參數之後，再次把FileSystemWatcher的觸發事件開啟
}
}
測試方法：
如果是在Visual Studio的debug階段，記得要去改OOXX.vshost.exe.config的設定檔，才能進入OnChange事件喔
如果已經發行到正式機的話，改OOXX.exe.config就可以進入OnChanged事件了
大概是這樣………
