[求助]请各位高手帮我查一下填充功能的代码不出效果？

由于需要对已加载的BMP图片实现局布颜色显示，仿小画家的填充功能利用API函数对图形用局布填充。由于需要显示的地方显示有多处，我就写了一个子过程。在测试的界面上，有一个按钮，和一个picturebox（已加载了一个BMP）,我的目的是，按一下按钮，系统则在按相对坐标指定点，以指定的颜色进行填充一个封闭的区域。
代码如下：在VB6.0下运行界面没有相应的变化。我不知道是哪里错了：

Public Declare Function ExtFloodFill Lib "gdi32" (ByVal hdc As Long, ByVal X As Long, _
ByVal Y As Long, ByVal crColor As Long, ByVal fuFillType As Long) As Long

Private Sub StartFill(X As Long, Y As Long, Color As Long)

Dim FillPtcul As Long, Result As Long
Const FLOODFILLSURFACE = 1

Picture1.DrawStyle = vbSolid
Picture1.DrawMode = 13
Picture1.DrawWidth = 1
Picture1.FillStyle = vbFSSolid
FillPtcul = Picture1.Point(X, Y)

Picture1.FillColor = Color

Result = ExtFloodFill(Picture1.hdc, X, Y, FillPtcul, FLOODFILLSURFACE)

'Picture1.FillStyle = 1  'Default (Transparent)

Picture1.Refresh

End Sub

Private Sub Command2_Click(Index As Integer)

  StartFill 2430, 3870, &H8000000F/相对坐标

End Sub