How can I monitor CPU and ram usage in Delphi?

There are several ways to monitor CPU and RAM usage in Delphi, one of the most common ways is to use the Windows Management Interface (WMI) to retrieve information about the system’s performance.

Here is an example of how to use WMI in Delphi to monitor CPU and RAM usage:

Declare the IWbemServices and IWbemLocator interfaces in the implementation section of your unit:

uses
  ActiveX, Variants, ComObj;

var
  WbemLocator: IWbemLocator;
  WbemServices: IWbemServices;

uses

ActiveX, Variants, ComObj;

var

WbemLocator: IWbemLocator;

WbemServices: IWbemServices;

Initialize the WbemLocator and WbemServices objects in the form’s OnCreate event:

procedure TForm1.FormCreate(Sender: TObject);
begin
  CoInitialize(nil);
  WbemLocator := CreateOleObject(‘WbemScripting.SWbemLocator’) as IWbemLocator;
  WbemServices := WbemLocator.ConnectServer(‘.’, ‘root\CIMV2’, ”, ”, ”, ”, 0, nil);
end;

procedure TForm1.FormCreate(Sender: TObject);

begin

CoInitialize(nil);

WbemLocator := CreateOleObject(‘WbemScripting.SWbemLocator’) as IWbemLocator;

WbemServices := WbemLocator.ConnectServer(‘.’, ‘root\CIMV2’, ”, ”, ”, ”, 0, nil);

end;

This connects to the local WMI namespace (indicated by the ‘.’) and the ‘root\CIMV2’ namespace, which is the default namespace for performance counters on Windows.

Use the ExecQuery method of the WbemServices object to query for the CPU and RAM usage:

function TForm1.GetCPUUsage: Integer;
var
  objWMIService: OLEVariant;
  colItems: OLEVariant;
  colItem: OLEVariant;
  oEnum: IEnumvariant;
  iValue: LongWord;
begin
  objWMIService := GetObject(‘winmgmts:\\localhost\root\CIMV2’);
  colItems := objWMIService.ExecQuery(‘SELECT * FROM Win32_Processor’, ‘WQL’, 0);
  oEnum := IUnknown(colItems._NewEnum) as IEnumVariant;
  if oEnum.Next(1, colItem, nil) = 0 then
  begin
    iValue := colItem.LoadPercentage;
    Result := iValue;
  end;
end;

function TForm1.GetCPUUsage: Integer;

var

objWMIService: OLEVariant;

colItems: OLEVariant;

colItem: OLEVariant;

oEnum: IEnumvariant;

iValue: LongWord;

begin

objWMIService := GetObject(‘winmgmts:\\localhost\root\CIMV2’);

colItems := objWMIService.ExecQuery(‘SELECT * FROM Win32_Processor’, ‘WQL’, 0);

oEnum := IUnknown(colItems._NewEnum) as IEnumVariant;

if oEnum.Next(1, colItem, nil) = 0 then

begin

iValue := colItem.LoadPercentage;

Result := iValue;

end;

function TForm1.GetRAMUsage: Cardinal;
var
  objWMIService: OLEVariant;
  colItems: OLEVariant;
  colItem: OLEVariant;
  oEnum: IEnumvariant;
  FreeMemory, TotalMemory: Cardinal;
begin
  objWMIService := GetObject(‘winmgmts:\\localhost\root\CIMV2’);
  colItems := objWMIService.ExecQuery(‘SELECT * FROM Win32_OperatingSystem’, ‘WQL’, 0);
  oEnum := IUnknown(colItems._NewEnum) as IEnumVariant;
  if oEnum.Next(1, colItem, nil) = 0 then
  begin
    FreeMemory := colItem.FreePhysicalMemory;
    TotalMemory := colItem.TotalVisibleMemorySize;
    Result := (TotalMemory – FreeMemory)
  end;
end;

function TForm1.GetRAMUsage: Cardinal;

var

objWMIService: OLEVariant;

colItems: OLEVariant;

colItem: OLEVariant;

oEnum: IEnumvariant;

FreeMemory, TotalMemory: Cardinal;

begin

objWMIService := GetObject(‘winmgmts:\\localhost\root\CIMV2’);

colItems := objWMIService.ExecQuery(‘SELECT * FROM Win32_OperatingSystem’, ‘WQL’, 0);

oEnum := IUnknown(colItems._NewEnum) as IEnumVariant;

if oEnum.Next(1, colItem, nil) = 0 then

begin

FreeMemory := colItem.FreePhysicalMemory;

TotalMemory := colItem.TotalVisibleMemorySize;

Result := (TotalMemory – FreeMemory)

end;

Use the GetCPUUsage and GetRAMUsage functions to retrieve the current CPU and RAM usage:

procedure TForm1.UpdateUsage;
begin
  CPULabel.Caption := IntToStr(GetCPUUsage) + ‘%’;
  RAMLabel.Caption := IntToStr(GetRAMUsage div 1024) + ‘MB’;
end;

procedure TForm1.UpdateUsage;

begin

CPULabel.Caption := IntToStr(GetCPUUsage) + ‘%’;

RAMLabel.Caption := IntToStr(GetRAMUsage div 1024) + ‘MB’;

end;

In this example, we are displaying the usage as a percentage for CPU and in MegaBytes for RAM

To update the usage regularly, you can use a timer to call the UpdateUsage method at a certain interval.

procedure TForm1.FormCreate(Sender: TObject);
begin
  Timer1.Interval := 1000;
  Timer1.Enabled := True;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  UpdateUsage;
end;

procedure TForm1.FormCreate(Sender: TObject);

begin

Timer1.Interval := 1000;

Timer1.Enabled := True;

end;

procedure TForm1.Timer1Timer(Sender: TObject);

begin

UpdateUsage;

end;

This will update the usage every 1000ms (1s).

Make sure to release the resources when you are done using the WMI:

Delphi/Pascal

procedure TForm1.FormDestroy(Sender: TObject); begin WbemServices := nil; WbemLocator := nil; CoUninitialize; end;

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procedure TForm1.FormDestroy(Sender: TObject);
begin
  WbemServices := nil;
  WbemLocator := nil;
  CoUninitialize;
end;

It is important to note that this is just an example of how to use WMI in Delphi to monitor CPU and RAM usage, and it could be improved with error checking and handling, and also there are other ways to monitor the system performance like using the GetPerformanceInfo function in the Windows API, or by reading the values of certain performance counters directly.

How can I monitor CPU and ram usage in Delphi?

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