Established in automatic in class 1, I entrust
Public delegate void methordDele (string STR);
Private methordDele deleInstance;
Public Display_listview methordDele (del)
{
DeleInstance=del;
}
Public void Display (string STR)
{
DeleInstance (STR);
}

2 in the main window procedure perform entrusted function:
Private Display_listview dispaly_listview;//display interface to entrust
Private void Form1_Load (object sender, EventArgs e)
{
Dispaly_listview=new Display_listview (new Display_listview methordDele (DO_display));
}
Private void DO_display (string STR)
{
}
Why the program execution to deleInstance (STR); After not turned into the main window function yet private void DO_display (string STR)?