Contains methode in Visual c++ NET 05

[miki]

Dear Sir, This below what I do that is not working I do know why ?

I need to verify if what I capture in the field j01 of my form is inside "APC" string.

This is not working. I don't understand.

Help me

private: System::Void j01_Leave(System::Object^ sender, System::EventArgs^ e) {
String^ pta = "APC";

if(this->j01->Text->Trim()->Contains(pta)== false)
{
::MessageBox::Show("Code Pointage inexistant");
this>j01>Text = "";
this>j01>Focus();
}
}