Get the system process and end a specified process (C #)

The process itself thought of another way to do

To modify the registry first:
Hkey_local_machine\\system\\currentcontrolset\\service\\perfproc\\performance
Under: Disable performance counters is changed to 0

Get the current process of the system and add it to the listbox:
system.diagnostics.process[] Processoncomputer = System.Diagnostics.Process.GetProcesses ();
foreach (System.Diagnostics.Process p in Processoncomputer)
{
THIS.LISTBOX1.ITEMS.ADD (P.processname);
}

To close a specified process:
system.diagnostics.process[] Process = System.Diagnostics.Process.GetProcessesByName ( This.listBox1.SelectedItem.ToString ());

foreach (System.Diagnostics.Process p in Process)
{
P.kill ();
}

However, this will close all instances of the process, such as if you open more than one ie, all the IE windows will be closed.

The following implementation closes a specific instance of IE
First declare a ArrayList:
ArrayList windowhandle = new ArrayList ();

Gets all instances of the specified process, puts it in a ListBox, and places the main window's handle in the ArrayList:
system.diagnostics.process[] Processoncomputer = System.Diagnostics.Process.GetProcessesByName ( This.listBox1.SelectedItem.ToString ());
foreach (System.Diagnostics.Process p in Processoncomputer)
{
THIS.LISTBOX2.ITEMS.ADD (p.mainwindowtitle);//Display the title of the main form in the listbox
Windowhandle.add (P.mainwindowhandle);
}

The handle and ArrayList of the main window of the specified process are turned off if they are met
system.diagnostics.process[] Process = System.Diagnostics.Process.GetProcessesByName ( This.listBox1.SelectedItem.ToString ());
foreach (System.Diagnostics.Process p in Process)
{
if (P.mainwindowhandle = = (System.IntPtr) (Windowhandle[this.listbox2.selectedindex))
{
P.kill ();
This.listBox2.Items.RemoveAt (This.listBox2.SelectedIndex);
}
}

This will close the process with the main form, but not the main form.
And please give us a lot of advice