我想在C#的Metro应用程序中获取日期顺序的文件列表

我认为这段代码应该这样做,

var queryOptions = new QueryOptions(CommonFileQuery.OrderByDate,new[] { ".xml" });
queryOptions.FolderDepth = FolderDepth.Deep;
StorageFolder folder = await ApplicationData.Current.LocalFolder.CreateFolderAsync("Recent",CreationCollisionoption.OpenIfExists);

StorageFileQueryResult query = folder.CreateFileQueryWithOptions(queryOptions);

var files = await query.GetFilesAsync();

但这给了我以下错误：

WinRT information: The requested enumeration option is not available
for this folder because it is not within a library or homegroup. Only folders within a library or a homegroup support all enumeration options.

有没有办法从Local文件夹中的目录中读取文件时按日期顺序获取文件列表？

您可以恢复文件,然后使用LINQ to Objects为您执行排序.

我刚刚在Visual Studio中创建了一个新的空白XAML / C# Windows应用商店应用.我尝试使用以下代码在Documents文件夹中创建一个文件：

// DEBUG ONLY:
StorageFile file = await KNownFolders.DocumentsLibrary.CreateFileAsync("hey lol.txt");

但它抛出了这个异常(我预期)：

WinRT information: Access to the specified location (DocumentsLibrary) requires a capability to be declared in the manifest.

哪个好.我期待它.所以我转到Package.appxmanifest并转到Capabilities选项卡,令我惊讶的是,没有列出“DocumentsLibrary”功能.

如果它不存在,我该如何启用它？

看起来你的答案是 here.作者在VS2012中显示它,但是从VS2013的列表中删除,引用了MS策略来访问该特定文件夹.

[Although] this capability is gone just from the UI,you still can open appxmanifest source and manually add the capability. The result will probably be the same as before – failure of certification for individual developers,so you better stay away from this trick. Microsoft strongly recommend against using Documents Library capability,suggesting Folder and File Pickers instead.

我需要找到以下代码的等价物,以便在便携式库中使用：

Public Overridable Function GetPropertyValue(ByVal p_propertyName As String) As Object
        Dim bf As System.Reflection.BindingFlags
        bf = Reflection.BindingFlags.IgnoreCase Or Reflection.BindingFlags.Public Or Reflection.BindingFlags.Instance Or Reflection.BindingFlags.NonPublic
        Dim propInfo As System.Reflection.PropertyInfo = Me.GetType().GetProperty(p_propertyName,bf)
        Dim tempValue As Object = nothing

        If propInfo Is nothing Then
            Return nothing
        End If

        Try
            tempValue = propInfo.GetValue(Me,nothing)

        Catch ex As Exception
            Errors.Add(New Warp10.Framework.BaSEObjects.BaseErrorMessage(String.Format("Could not Get Value from Property {0},Error was :{1}",p_propertyName,ex.Message),-1))
            Return nothing
        End Try

        Return tempValue

    End Function

BindingFlags似乎不存在. System.Reflection.PropertyInfo是一个有效的类型,但我无法弄清楚如何填充它.有什么建议？

对于Windows 8 / Windows Phone 8,许多此Reflection功能已移至新的TypeInfo类.您可以找到更多信息 in this MSDN doc.有关包括运行时属性(包括例如继承的属性)的信息,您也可以使用新的 RuntimeReflectionExtensions class(可以通过LINQ简单地进行过滤).

虽然这是C#代码(我的道歉:)),但这里使用这个新功能是完全相同的：

public class TestClass
{
    public string Name { get; set; }

    public object GetPropValue(string propertyName)
    {
        var propInfo = RuntimeReflectionExtensions.GetRuntimeProperties(this.GetType()).Where(pi => pi.Name == propertyName).First();
        return propInfo.GetValue(this);
    }
}

如果您只关心在类本身声明的属性,那么此代码甚至更简单：

public class TestClass
{
    public string Name { get; set; }

    public object GetPropValue(string propertyName)
    {
        var propInfo = this.GetType().GetTypeInfo().GetDeclaredProperty(propertyName);
        return propInfo.GetValue(this);
    }
}