C#

string search = "x1";
string status = (ConnectionStatus) ? "Connected" : "Disconnected";
int i_row = myListView.Items.IndexOfKey(search);
myListView.SelectedItems[i_row].SubItems[3].Text = status;

//If i_row is not needed for anything else delete the next line
            int i_row;
            string search = "x1";
            string status = (ConnectionStatus) ? "Connected" : "Disconnected";
            for (int i = 0; i < myListView.Items.Count; i++)
            {
                if (!(myListView.Items[i].SubItems.IndexOfKey(search) == -1))
                {
                    //If i_row is not needed for anything else delete the next line
                    i_row = i;
                    myListView.Items[i].SubItems[3].Text = status;
                    break;
                }
            }

string search = "x1";
string status = (ConnectionStatus) ? "Connected" : "Disconnected";
for (int i = 0; i < myListView.Items.Count; i++)            {
{
    ListViewItem item = myListView.Items;
    if(item.SubItems[4] == search)
        items.SubItems[3].Text = status
}

private static TestApp.MainForm m_InstanceRef = null;
public static TestApp.MainForm InstanceRef
  {
  get
    {
    return m_InstanceRef;
    }
  set
    {
     m_InstanceRef = value;
    }
  }

KeyHook.InstanceRef = this;
KeyHook.Listen();

InstanceRef.EnableCheck();