error-handling - 使用GetText从剪贴板获取文本-仅在剪贴板上显示图形时避免错误

Question

这是我在这里提出的问题的扩展:

Get text from clipboard using GetText - avoid error on empty clipboard

这个问题的答案可以很好地避免剪贴板为空的错误，但是现在我发现我还必须处理一个仅包含图形而不包含文本的剪贴板，并且这种情况会超出剪贴板的空过滤条件。

因此，如果剪贴板上只有图形而没有文本，我该如何终止该过程？

Answer 1

您可以使用此代码测试剪贴板中数据的格式是否为图像。

Option Explicit

Private Declare Function OpenClipboard Lib "user32" _
(ByVal hwnd As Long) As Long

Private Declare Function GetClipboardData Lib "user32" _
(ByVal wFormat As Integer) As Long

Private Declare Function CloseClipboard Lib "user32" () As Long

Const CF_BITMAP = 2

Sub Sample()
    Dim RetClpB As Long
    Dim RetBmp As Long

    '~~> Open Clipboard
    RetClpB = OpenClipboard(0&)

    '~~> Check if we were successful
    If RetClpB <> 0 Then
        '~~> Test if the data in Clipboard is an image by
        '~~> trying to get a handle to the Bitmap
        RetBmp = GetClipboardData(CF_BITMAP)

        '~~> If found
        If RetBmp <> 0 Then
            MsgBox "data in clipboad is an image"
        Else
            MsgBox "data in clipboad is not an image"
        End If
    End If

    '~~> Close Clipboard
    RetClpB = CloseClipboard
End Sub