Public Class Form1
Private Declare Function mcisendstring Lib "winmm.dll " Alias "mcisendstringA" _
(ByVal ipstrCommand As String, ByVal ipstrReturnString As String, ByVal ureturnlength As Long, ByVal hwndcallback As Long) As Long
Private Declare Function mciexecute Lib "winmm.dll" _
(ByVal ipstrCommand As String) As Long
Dim flag As Boolean
Private Sub end1_Click(sender As Object, e As EventArgs) Handles end1.Click
If flag Then mciexecute("Close avi")
End Sub
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
flag = False
play.Enabled = False
stop1.Enabled = False
End Sub
Private Sub open_Click(sender As Object, e As EventArgs) Handles open.Click
Dim returnstr As String
Dim str1 As String
str1 = mcisendstring("open" & OpenFileDialog1.FileName & "alias avi style child parent" + Str$(PictureBox1.FindForm.Handle), returnstr, 128, 0)
mciexecute("set avi seek exactly on")
mciexecute("window avi handle" + Str(PictureBox1.Handle))
play.Enabled = True
stop1.Enabled = True
str1 = mcisendstring("infi avi product", returnstr, 128, 0)
Me.Text = OpenFileDialog1.FileName
mciexecute("cue avi to 0")
mciexecute（"play avi from 0 to 1"）
flag = True
End Sub
Private Sub stop1_Click(sender As Object, e As EventArgs) Handles stop1.Click
mciexecute（"pause avi"）
End Sub
Private Sub play_Click(sender As Object, e As EventArgs) Handles play.Click
mciexecute（"play avi"）
End Sub
End Class
中的这句 str1 = mcisendstring("open" & OpenFileDialog1.FileName & "alias avi style child parent" + Str$(PictureBox1.FindForm.Handle), returnstr, 128, 0)
“System.InvalidCastException”类型的未经处理的异常在 Microsoft.VisualBasic.dll 中发生
其他信息: 参数“Number”不能转换为数值。
怎么改？？？？？？？？？？？？？？

表示没看出来，你去
看看你的
mcisendstring的声明里，某些变量的as有没有写错