Call a controller function into a view

I've got a Controller (UsersController) with a function :

 public function project_donated($project_id)
{
    return Donation
        ::groupBy('donations.project_id')
        ->selectRaw('sum(donations.amount) as sum, donations.project_id, projects.*')
        ->where('donations.project_id', $project_id)
        ->join('projects', 'donations.project_id', '=', 'projects.id')
        ->get()
        ->toArray();
}

This function works fine.

I return this function into the same UserController to my view with :

$project_donated = $this->project_donated($project_id);
return view('users.show', compact('user', 'countries', 'donation_user' , 'user_donated', 'project_donated'));

But, I cannot defind $project_id into my controller, I need to specify it into my view, so into my view, I had this line :

<?php
$project_id = $ngo->project->ngo->id;
$project_donated = UsersController::project_donated($project_id);
?>

But I've got an error : Class 'UsersController' not found.

I'm not sure I'm doing this the right way.

via Kaherdin