Printer 为何在点个按钮时,可打印出内容,为何用别的按钮调用这个这按钮时,为何打印机只走纸,却没有内容呢?

Question

        Printers.Printer.PrinterIndex:=1;
        printers.Printer.Copies:=2;
        printers.Printer.BeginDoc;
        printers.Printer.Canvas.Font.Size:=24;
        printers.Printer.Canvas.Font.Color:=clred;         //printers.Printer.Orientation:=SetOrienatiion;
        y:=y+150;
        x:=100;
        printers.Printer.Canvas.TextOut(x+300,y,'大碗厨点菜单');
        printers.Printer.Canvas.Font.Size:=10;
        y:=y+100;
        printers.Printer.Canvas.TextOut(x,y,'-------------------------------------');
        printers.Printer.EndDoc;以上打印程序,为何在点个按钮时,可打印出内容,为何用别的按钮调用这个这按钮时,为何打印机只走纸,却没有内容呢?

Answer 1

y:=y+150;y值不确定 
在未赋初值时, 它是一个不确定的值, 有可能很大很大.....因为它所在的栈内存是一些随机数据所以就走纸