Check if an OneDrive file is available in local PC.

OneDriveFile.cs

using System;
using System.IO;
using System.Linq;

private class OneDriveFile
{
    public static void CheckFileIsAvailable(string filePath)
    {
        var fileAttribute = File.GetAttributes(filePath);
        Console.WriteLine("Attributes: {0}", fileAttribute);

        var isAvailable = !fileAttribute.HasFlag(FileAttributes.Offline);
        Console.WriteLine("Available: {0}", isAvailable);

        try
        {
            new FileStream(filePath, FileMode.Open, FileAccess.Read).Close();
            Console.WriteLine("CAN read.");
        }
        catch (IOException)
        {
            Console.WriteLine("CANNOT read.");
        }
    }

    public void CheckFiles()
    {
        var folderPath = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), "SkyDrive", "Reference");

        CheckFileIsAvailable(Path.Combine(folderPath, "容量計算.xlsx"));
        // Attributes: Archive
        // Available: True
        // CAN read.

        CheckFileIsAvailable(Path.Combine(folderPath, "暗号技術.pdf"));
        // Attributes: Hidden, System, Archive, SparseFile, ReparsePoint, Offline
        // Available: False
        // CANNOT read.

        Console.ReadLine();
    }
}