C++

Tapping processes using WMI - I

In the last article we saw how to list the processes currently running on the local machine. In this article we will see a similar application that displays the processes currently running on the machine, but with additional functionality. We will display additional information about each process and also extend the program to view the processes running on a remote machine. The application will also allow us to terminate the running process.

Create a WinForm application and place controls on it as shown below:

Change the names of controls as shown in the following table.

When the application is executed, it displays the list of processes and their information of the local machine. To view the processes of remote machine, the user should enter the machine name, username and password and click the Refresh button.

To terminate the process, the user should select the process from list view control and click the ‘Terminate Process’ button.

Let us first add code to the constructor of the Form1 class after the call to the InitializeComponent( ) method to display processes of the current machine.

ManagementClass mc = new ManagementClass ( @”root\cimv2:Win32_Process” ) ;
ManagementObjectCollection mobjects = mc.GetInstances( ) ;
addprocesses ( mobjects ) ;

The object collection returned by the GetInstances( ) method is passed to a user-defined function addprocesses( ). We have separated code to add the processes in a function, because we need to execute the same code again when the user clicks the ‘Refresh’ button.

The addprocesses( ) function is given below:

public void addprocesses ( ManagementObjectCollection moc )

     {
          m_plist.Items.Clear( ) ;
         string[ ] items = new string [ 5 ] ;
         foreach ( ManagementObject mo in moc )

         {
                items [ 0 ] = mo [ “Caption” ].
                ToString( ) ;
                 items [ 1 ] = mo [ “ProcessId” ].
                ToString( ) ;
                 int vs = Int32.Parse ( mo [ “WorkingSetSize” ].ToString( ) ) ;
                 vs = vs / 1024 ;
                 items [ 2 ] = vs.ToString( ) + “ Kb” ;

                       if ( mo [ “ExecutablePath” ] == null )
                          items [ 3 ] = “NA” ;

                      else

                           items [ 3 ] = mo
                           [ “ExecutablePath” ].ToString( ) ;
                           items [ 4 ] = mo [ “Priority” ].ToString( ) ;
                          ListViewItem lvitems = new
                          ListViewItem ( items ) ;
                          m_plist.Items.Add ( lvitems ) ;

              }

      }

In this function, at first, we have removed all the previously added list items from the control by calling the Clear( ) method. Next, we have enumerated the objects from the collection passed to this function in a foreach loop. Each object in the collection represents a process. We will display the process name, process ID, memory the process is using, path of the EXE and priority of process in the list control. To obtain this information of the process, we have used various properties of the Win32_Process class. They are given below:

• Caption: It returns the name of the process.
• ProcessId: It returns the ID of the process.
• WorkingSetSize: It returns the amount of memory (in bytes) the process requires to run efficiently.
• ExecutablePath: It returns the path of the process.
• Priority: It returns the priority of the process.

To display the values returned by these properties, firstly we have created an array of five strings. Since the properties return value of type object we have converted them to strings.

The WorkingSetSize property returns the memory size in bytes. We have converted bytes into kilobytes before converting them to string.

After populating the string array, we have created an object of the ListViewItem and passed the array to its constructor. The 0th element in the array will be treated as new list item, and rest of the elements as its sub-items. Then we have called the Add( ) method to add the new list item to the list control.

So, when we execute the application, it looks as shown in the following figure.

We can now enter the machine name, user name and password and click the ‘Refresh’ button to view the processes of that machine. We will see the ‘Refresh’ button handler next time.

Yashavant Kanetkar, one of the first Express Computer columnists, is an established software expert, speaker and author with several best-sellers to his credit, including titles like “Let Us C” and the “Fundas” series. Contact him at kanetkar@dcubesoft.com