//创建缓存文件
//文件将以随机的Guid命名，完成写入时再命名为期望的文件名
//此举有助于防止写入一半时程序非法终止而产生损坏的缓存文件
public static async Task <TempStorageFile?> CreateCacheFileAsync(string Filename)
{
Guid guid;
var test = Guid.TryParse(Filename, out guid);
//避免使用GUID作为文件名
if (test)
{
return(null);
}
do
{
guid = Guid.NewGuid();
}while (await GetCachedFileAsync(guid.ToString()) != null);
var cacheFolder = await getCacheFolderAsync();
var newFile = await cacheFolder.CreateFileAsync(guid.ToString());
TempStorageFile result = new TempStorageFile();
result.ExpectedName = Filename;
result.File = newFile;
return(result);
}
//完成写入缓存文件
//ForceUpdate: 是否覆盖已有的文件
public static async Task <bool> FinishCachedFileAsync(TempStorageFile File, bool ForceUpdate = false)
{
try
{
if (await GetCachedFileAsync(File.ExpectedName) != null)
{
if (ForceUpdate)
{
await DeleteCachedFileAsync(File.ExpectedName);
}
else
{
return(false);
}
}
await File.File.MoveAsync(await getCacheFolderAsync(), File.ExpectedName);
return(true);
}
catch
{
return(false);
}
}