Delphi-Help

uses 

  Registry; 

function GetInstalledMailClients(AList: TStrings): Boolean; 

const 

  RegClientsRoot = '\SOFTWARE\Clients'; 

  RegClientsMail = '\Mail'; 

  RegClientsOpenCmd = '\shell\open\command'; 

var 

  reg: TRegistry; 

begin 

  Result := True; 

  try 

    AList.Clear; 

    reg := nil; 

    reg := TRegistry.Create; 

    try 

      with reg do 

      begin 

        CloseKey; 

        RootKey := HKEY_LOCAL_MACHINE; 

        if OpenKeyReadOnly(RegClientsroot + RegClientsMail) then 

          if HasSubKeys then 

            GetKeyNames(AList); 

      end; 

    finally 

      if Assigned(reg) then reg.Free; 

    end; 

  except 

    Result := False; 

  end; 

end; 

procedure TForm1.Button1Click(Sender: TObject); 

begin 

  GetInstalledMailClients(ListBox1.Items); 

end;