C# 获取磁盘剩余空间

//单位ＭＢ
public static long GetHardDiskSpace(string str_HardDiskName)
{
long totalSize = 0;
str_HardDiskName = str_HardDiskName + ":\\";
System.IO.DriveInfo[] drives = System.IO.DriveInfo.GetDrives();
foreach (System.IO.DriveInfo drive in drives)
{
if (drive.Name == str_HardDiskName)
{
totalSize = drive.TotalFreeSpace / (1024 * 1024);
}
}
return totalSize;
}

string AppPath = Application.StartupPath.ToString();
string volume = AppPath.Substring(0, AppPath.IndexOf(':'));
long freespace = GetHardDiskSpace(volume);