How to get the value of StartingOffset properties in class Win32_DiskPartition

I got a message

Method 'StartingOffset' not supported by automation object.

Here is a small part of my code:

colLogicalDisks := objWMIService.ExecQuery('ASSOCIATORS OF {Win32_DiskPartition.DeviceID="'+VarToStr(objPartition.DeviceID)+'"} WHERE AssocClass = Win32_LogicalDiskToPartition');
oEnumLogical  := IUnknown(colLogicalDisks._NewEnum) as IEnumVariant;
    while oEnumLogical.Next(1, objLogicalDisk, iValue) = 0 do
    begin
        ShowMessage(objLogicalDisk.StartingOffset);
        driveletter := string(objLogicalDisk.DeviceID);

        if driveletter = ExtractFileDrive(GetCurrentDir) then
        begin
            SetLength(result, 6);
            result[0] := string(objdiskDrive.DeviceID);
            result[1] := string(objdiskDrive.Model);
            result[2] := string(objdiskDrive.MediaType);
            result[3] := string(ConvertBytes(objdiskDrive.Size));
            result[4] := string(objLogicalDisk.Description);
            result[5] := string(ConvertBytes(objLogicalDisk.Size));
        end;
        objLogicalDisk:=Unassigned;
    end;

Source code from here

Solution

Your code fails because the objLogicalDisk variable holds an instance to the Win32_LogicalDisk WMI class and you need access to the Win32_DiskPartition class. Also your sample code is not complete but it seems which your are using the code posted here. If that is the case you can access to the StartingOffset property via the objPartition variable (objPartition.StartingOffset)