我找不到任何文件说明如何正确使用OneDrive在C＃中存储和同步应用程序文件跨设备。
我已经阅读了OneDrive开发中心的文档，但我不懂http代码（仅自学C＃）。
我有点理解使用增量方法从OneDrive获取更改的文件，然后保存在本地，但我无法确切地弄清楚如何做到这一点，因此通过使用GetAsync<>方法手动检查本地与OneDrive的差异来解决该问题。
对我来说，当前实现（下面是参考）似乎比API中可能更好的处理方式要笨拙一些。
此外，似乎没有相反的“增量”函数？也就是说，我将文件写入应用程序本地，然后告诉OneDrive同步更改，但似乎没有这样的函数。这是因为我需要使用PutAsync<>方法上传它吗？（目前我正在执行此操作）
public async Task<T> ReadFromXML<T>(string gamename, string filename)
{
string filepath = _appFolder + @"\" + gamename + @"\" + filename + ".xml";
T objectFromXML = default(T);
var srializer = new XmlSerializer(typeof(T));
Item oneDItem = null;
int casenum = 0;
//_userDrive is the IOneDriveClient
if (_userDrive != null && _userDrive.IsAuthenticated)
{
try
{
oneDItem = await _userDrive.Drive.Special.AppRoot.ItemWithPath(filepath).Request().GetAsync();
if (oneDItem != null) casenum += 1;
}
catch (OneDriveException)
{ }
}
StorageFile localfile = null;
try
{
localfile = await ApplicationData.Current.LocalFolder.GetFileAsync(filepath);
if (localfile != null) casenum += 2;
}
catch (FileNotFoundException)
{ }
switch (casenum)
{
case 0:
//neither exist. Throws exception to tbe caught by the calling method, which should then instantiate a new object of type <T>
throw new FileNotFoundException();
case 1:
//OneDrive only - should copy the stream to a new local file then return the object
StorageFile writefile = await ApplicationData.Current.LocalFolder.CreateFileAsync(filepath, CreationCollisionOption.ReplaceExisting);
using (var newlocalstream = await writefile.OpenStreamForWriteAsync())
{
using (var oneDStream = await _userDrive.Drive.Special.AppRoot.ItemWithPath(filepath).Content.Request().GetAsync())
{
oneDStream.CopyTo(newlocalstream);
}
}
using (var newreadstream = await writefile.OpenStreamForReadAsync())
{ objectFromXML = (T)srializer.Deserialize(newreadstream); }
break;
case 2:
//Local only - returns the object
using (var existinglocalstream = await localfile.OpenStreamForReadAsync())
{ objectFromXML = (T)srializer.Deserialize(existinglocalstream); }
break;
case 3:
//Both - compares last modified. If OneDrive, replaces local data then returns the object
var localinfo = await localfile.GetBasicPropertiesAsync();
var localtime = localinfo.DateModified;
var oneDtime = (DateTimeOffset)oneDItem.FileSystemInfo.LastModifiedDateTime;
switch (oneDtime > localtime)
{
case true:
using (var newlocalstream = await localfile.OpenStreamForWriteAsync())
{
using (var oneDStream = await _userDrive.Drive.Special.AppRoot.ItemWithPath(filepath).Content.Request().GetAsync())
{ oneDStream.CopyTo(newlocalstream); }
}
using (var newreadstream = await localfile.OpenStreamForReadAsync())
{ objectFromXML = (T)srializer.Deserialize(newreadstream); }
break;
case false:
using (var existinglocalstream = await localfile.OpenStreamForReadAsync())
{ objectFromXML = (T)srializer.Deserialize(existinglocalstream); }
break;
}
break;
}
return objectFromXML;
}