在Windows 8 RT中替换或重新创建文件将保留旧的DateCreated值 [英] Replacing or recreating a file in Windows 8 RT keeps the old DateCreated value

问题描述

我尝试缓存Windows Store应用程序的文件中的数据，并使用DateCreated值确定它是否过期。

我第一次尝试这样做：

$ $ $ code var文件=等待rootFolder.CreateFileAsync（文件名，Windows.Storage.CreationCollisionOption.ReplaceExisting）;

FileIO.WriteTextAsync（file，contents）;

但是当它保存文件时，只有DateModified值被更改，即使ReplaceExisting选项的注释清楚地表明，它重新创建了文件并替换了现有文件。

所以我决定强制它删除文件并重新创建它：

  var file =等待rootFolder.CreateFileAsync（文件名，Windows.Storage.CreationCollisionOption.ReplaceExisting）; 
 
 //强制删除，因为windows rt没有在上面的行中做它应该做的事情！ 
等待file.DeleteAsync（）; 
 file =等待rootFolder.CreateFileAsync（filename）; 
 
 FileIO.WriteTextAsync（file，contents）; 
  

但令人惊讶的是，我仍然得到相同的结果！该文件被删除，并重新创建OLD CREATION DATE！

这是一个错误，还是我在这里做错了？

解决方案

感谢大家的评论，事实证明修改日期是可用的，但是你必须通过GetBasicPropertiesAsync（）方法如下所示： http： //msdn.microsoft.com/en-us/library/windows/apps/windows.storage.fileproperties.basicproperties.datemodified.aspx

I'm attempting to cache data in a file for a Windows Store app, and using the DateCreated value to determine if it is out of date.

I first tried doing this:

    var file = await rootFolder.CreateFileAsync(filename, Windows.Storage.CreationCollisionOption.ReplaceExisting);

    FileIO.WriteTextAsync(file, contents);

but when it saves the file only the DateModified value is changed, even though the comments for the ReplaceExisting option clearly state that it recreates the file and replaces an existing one.

So I decided to force it to delete the file and recreate it with this:

    var file = await rootFolder.CreateFileAsync(filename, Windows.Storage.CreationCollisionOption.ReplaceExisting);

// force delete because windows rt is not doing what it's supposed to in the line above!!
await file.DeleteAsync();
file = await rootFolder.CreateFileAsync(filename);

FileIO.WriteTextAsync(file, contents);

but amazingly, I still get the same result! The file is deleted and recreated with the OLD CREATION DATE!

Is this a bug, or am I doing something wrong here?

解决方案

Thanks for the comments everyone, it turns out the Modified date IS available but you have to get it through the GetBasicPropertiesAsync() method as shown here: http://msdn.microsoft.com/en-us/library/windows/apps/windows.storage.fileproperties.basicproperties.datemodified.aspx

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