windows phone 8.1開發:檔案選取器FileSavePicker

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上一篇文章小夢分享了檔案選取器FileOpenPicker的用法,這篇文章我們繼續分享FileSavePicker的用法,FileSavePicker的用法幾乎和FileOpenPicker用法一模一樣.唯一的區別就是在FileOpenPicker中是通過FileTypeFilter屬性添家字串元素的,但是在FileSavePicker中是向FileTypeChoices屬性工作表示的集合中添加元素的.FileTypeChoices是字典類型,因此它的每一個元素都必須具有唯一的鍵名,對應的值是IList<string>類型.

下面我們通過將textbox的內容存入一個txt檔案來說明FileSavePicker的用法,過程和FileOpenPicker用法是一樣的.

就把代碼依次貼出來了:

   private void saveButton_Click(object sender, RoutedEventArgs e)        {            FileSavePicker savePicker = new FileSavePicker();            savePicker.FileTypeChoices.Add("TXT", new List<string>() { ".txt" });            savePicker.SuggestedFileName = "小夢";            savePicker.ContinuationData["Operation"] = "Save";            savePicker.PickSaveFileAndContinue();        }

protected override void OnActivated(IActivatedEventArgs args)        {                if (args is FileSavePickerContinuationEventArgs)            {                Frame rootFrame = Window.Current.Content as Frame;                if (!rootFrame.Navigate(typeof(MainPage)))                {                    throw new Exception("Failed to create target page");                }                var s = rootFrame.Content as MainPage;                s.SavePickerArgs = (FileSavePickerContinuationEventArgs)args;            }            Window.Current.Activate();        }

private FileSavePickerContinuationEventArgs savePickerArgs;        public FileSavePickerContinuationEventArgs SavePickerArgs        {            get { return savePickerArgs; }            set            {                savePickerArgs = value;                ContinuFileSavePicker(savePickerArgs);            }        }        private async void ContinuFileSavePicker(FileSavePickerContinuationEventArgs args)        {            if (args.ContinuationData["Operation"] as string == "Save" && args.File != null)            {                StorageFile txtFile = args.File;              await   FileIO.WriteTextAsync(txtFile, this.text.Text.ToString(), Windows.Storage.Streams.UnicodeEncoding.Utf8);            }        }

 

windows phone 8.1開發:檔案選取器FileSavePicker