I recently needed to write some code to determine the percentage of free disk space on a drive. I was a bit surprised when I found that this information wasn't immediately available in some .NET class. However, I did stumble upon the System.Management namespace. This namespace contains classes that allow a .NET programmer to query any of the vast array of Windows Management Instrumentation (WMI) classes. These classes allow a program to obtain all kinds of data about a system, including free and total disk space.
Here is some code that uses the ManagementObject class:
// get parms from the command line
DiskDrive = args[4].Replace(
":",
"").ToUpper();
// run the query
mo = new ManagementObject(string.Format("Win32_LogicalDisk.DeviceID=\"{0}:\"", DiskDrive));
// store results
FreeSpace = double.Parse(mo["FreeSpace"].ToString());
TotalSpace = double.Parse(mo["Size"].ToString());
CurrentValue = (int)Math.Round((FreeSpace / TotalSpace) * 100, 0);
Now, the example above does a direct query against a single instance of a WMI class. Sometimes this isn't possible. Some WMI classes return multiple instances, which need to be iterated. Here is an example that returns the status of a Windows Service:
// get parms from the command line
Service = args[2].ToString().ToUpper();
// run the query
Query = string.Format("select State,Name from Win32_BaseService where Name=\"{0}\"", Service);
mos = new ManagementObjectSearcher(Query);
// find the WMI instance for the indicated service
foreach (ManagementObject mo in mos.Get())
{
Name = mo["Name"].ToString().ToUpper();
if (Name == Service)
{
State = mo["State"].ToString();
}
}
See here and here for two of the MSDN pages that I used most.