vfp如何实现进度条

** test.prg
CREATE CURSOR tt (工序 I, 进度 C(10))
FOR i=1 TO 100
    INSERT INTO tt VALUES (i%4,"")
ENDFOR
GO TOP
of = CREATEOBJECT("form1")
of.show(1)
RETURN

DEFINE CLASS form1 as Form
    ADD OBJECT grid1 as _grid
ENDDEFINE

DEFINE CLASS _grid as Grid
    visible = .T.
    columncount = 2
    PROCEDURE init
        this.column1.width = 50
        this.column1.ControlSource = "tt.工序"
        this.column1.header1.caption = "工序"
        this.column1.DynamicBackColor = "ICASE(tt.工序==1,0xFF9090,tt.工序==2,0x90FF90,tt.工序==3,0x9090FF,0xFFFFFF)"
        this.column2.width = 100
        this.column2.ControlSource = ""
        this.column2.sparse = .F.
        this.column2.removeobject("Text1")
        this.column2.addobject("cb1", "ColorBar")
        this.column2.header1.caption = "进度"
    ENDPROC
ENDDEFINE

DEFINE CLASS ColorBar as Container
    visible = .T.
    backstyle = 0
    borderwidth = 0
    ADD OBJECT label1 as label WITH alignment=2,forecolor=0
    PROCEDURE BackStyle_ACCESS
        this.label1.width     = tt.工序*30
        this.label1.backcolor = ICASE(tt.工序==1,0xFF9090,tt.工序==2,0x90FF90,tt.工序==3,0x9090FF,0xFFFFFF)
        this.label1.caption   = TRANSFORM(INT(100*tt.工序/3))+"%"
        RETURN this.BackStyle
    ENDPROC
ENDDEFINE