Question

VB中用Picturebox显示图片的问题

VB中picturebox不能显示PNG格式图片。如果Picturebox显示到PNG图片的时候就出错。有什么办法不提示错误，直接Picturebox为空
有好的代码的话可以再另外加分！

Answer 1

其实最简单的是利用捕捉错误的方法，而且该方法适用于任何VB不兼容的图片格式的情况（当然包括PNG图片）：
Private Sub Command1_Click()
On Error Resume Next '开始捕捉错误
Picture1.Picture = LoadPicture(App.Path & "\1.NPG")
if err.Number <>0 then Picture1.Picture = LoadPicture() '如果不兼容则置空
End Sub

Answer 2

可以通过判断文件的扩展名，或者文件的格式，直接忽略掉这类文件。

判断文件扩展名是不是png

Private Function GetExt(ByVal sFileName As String) As String
GetExt = Right(sFileName, Len(sFileName) - InStrRev(sFileName, "."))
End Function

if lcase(GetExt("文件")) = "png" then
picture1.picture = loadpicture()
else
picture1.picture = loadpicture("文件")
end if

下面这个函数是判断文件格式是否是PNG的。

Private Function ImageIsPNG(ByVal sFileName As String) As Boolean
Const BUFFERSIZE As Long = 65535
Dim bBuf(BUFFERSIZE) As Byte
Dim iFN As Integer
iFN = FreeFile
ImageIsPNG = False
Open sFileName For Binary As iFN
Get #iFN, 1, bBuf()
Close iFN
If bBuf(0) = 137 And bBuf(1) = 80 And bBuf(2) = 78 Then
ImageIsPNG = True
End If
End Function

if ImageIsPNG("文件") then
picture1.picture = loadpicture()
else
picture1.picture = loadpicture("文件")
end if

其实png也可以通过gdi+显示的，

Answer 3

VB不兼容PNG格式图片，如果非要用就只能自己研究PNG格式了

Answer 4

给我发一个png图片我试一下，我想到了一个主意，试试看
Private Sub Command1_Click()
On Error GoTo 10000
Picture1.Picture = LoadPicture(App.Path & "\1.NPG")
10000:
Picture1.Picture = LoadPicture()
End Sub

Answer 5

错误陷阱呀。