怎么样可以捕获到鼠标进入和离开窗体呢?

这里要用到两个Api,即SetCapture和ReleaseCapture.

新建一个工程,将下面代码贴入代码区.按F5运行即可.

Option Explicit

Private Declare Function SetCapture Lib "user32" (ByVal hwnd As Long) As Long
Private Declare Function ReleaseCapture Lib "user32" () As Long

Private Sub Form_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
    With Form1
    If Not ((X < 0) Or (Y < 0) Or (X > .Width) Or (Y > .Height)) Then
       ReleaseCapture
       If .Caption <> "进来了" Then
          .Caption = "进来了"
       End If
       SetCapture .hwnd
    Else
       .Caption = "离开了"
    End If
    End With
End Sub

现在把鼠标移动到窗体内外试试看.

                                                                               --- 程序:唐细刚