How can I get the GUID of my disc partitions?

I'm using WMI to get all disk information, like drives, drive letters, etc. but I have not found out how I could get the UUID/GUID of each partition.

There are several WMI classes to access Disks and Partitions information:

• Win32_Volume
• Win32_DiskDrive
• Win32_DiskPartition

And these two, which relate the previous ones to each other:

• Win32_DiskDrivePhysicalMedia
• Win32_DiskDriveToDiskPartition

Specifically using Win32_Volume you can access the GUID of the existing partitions. You can test it from shell:

> wmic volume get Driveletter, DeviceID

You get data like this:

Using delphi, you can use some components, or one code like this (by Code Creator -Rodrigo Ruz-):

program GetWMI_Info;
{$APPTYPE CONSOLE}   
uses
  SysUtils, ActiveX, ComObj, Variants;
   
procedure  GetWin32_VolumeInfo;
const
  WbemUser            ='';
  WbemPassword        ='';
  WbemComputer        ='localhost';
  wbemFlagForwardOnly = $00000020;
var
  FSWbemLocator : OLEVariant;
  FWMIService   : OLEVariant;
  FWbemObjectSet: OLEVariant;
  FWbemObject   : OLEVariant;
  oEnum         : IEnumvariant;
  iValue        : LongWord;
begin;
  FSWbemLocator := CreateOleObject('WbemScripting.SWbemLocator');
  FWMIService   := FSWbemLocator.ConnectServer(WbemComputer, 'root\CIMV2', WbemUser, WbemPassword);
  FWbemObjectSet:= FWMIService.ExecQuery('SELECT * FROM Win32_Volume','WQL',wbemFlagForwardOnly);
  oEnum         := IUnknown(FWbemObjectSet._NewEnum) as IEnumVariant;
  while oEnum.Next(1, FWbemObject, iValue) = 0 do
  begin
    Writeln(Format('Description     %s',[String(VarToStrDef(FWbemObject.Description, ''))]));// String
    Writeln(Format('DeviceID        %s',[String(VarToStrDef(FWbemObject.DeviceID, ''))]));// String
    Writeln(Format('DriveLetter     %s',[String(VarToStrDef(FWbemObject.DriveLetter, ''))]));// String
    Writeln(Format('DriveType       %d',[Integer(VarToStrDef(FWbemObject.DriveType, ''))]));// Uint32
    Writeln(Format('Label           %s',[String(VarToStrDef(FWbemObject.Label, ''))]));// String
    Writeln(Format('Name            %s',[String(VarToStrDef(FWbemObject.Name, ''))]));// String
    Writeln(Format('SerialNumber    %d',[Integer(VarToStrDef(FWbemObject.SerialNumber, ''))]));// Uint32
    Writeln('');
    FWbemObject:=Unassigned;
  end;
end;

begin
 try
    CoInitialize(nil);
    try
      GetWin32_VolumeInfo;
    finally
      CoUninitialize;
    end;
 except
    on E:EOleException do
        Writeln(Format('EOleException %s %x', [E.Message,E.ErrorCode]));
    on E:Exception do
        Writeln(E.Classname, ':', E.Message);
 end;
 Writeln('Press Enter to exit');
 Readln;
end.

The result looks like this: