Developers can use the CF_HTML clipboard format (HTML
Format) to share HTML data with other applications that understand HTML, such
as Microsoft Office and Microsoft Internet Explorer.
CF_HTML is
entirely a text-based format that includes a description, a context, and a
fragment within that context. When you are building data to send to the
clipboard, you must include a description of the data to indicate the clipboard
version and the offsets for the context and fragment. You can use the PutHTMLClipboard procedure described later in this article to simplify this task.
Start a new Standard EXE Project in Visual Basic. Form1 is
created by default.
Add two CommandButton controls to Form1. Change the Caption property of Command1 to Put HTML, and change the Caption property of Command2 to Get HTML.
On the Project menu, choose Add Module to add a standard BAS module to the project.
Add the following code to the module window:
Option Explicit
Private Declare Function CloseClipboard Lib "user32" () As Long
Private Declare Function OpenClipboard Lib "user32" (ByVal hWnd As Long) _
As Long
Private Declare Function GlobalAlloc Lib "kernel32" ( _
ByVal wFlags As Long, ByVal dwBytes As Long) As Long
Private Declare Function SetClipboardData Lib "user32" ( _
ByVal wFormat As Long, ByVal hMem As Long) As Long
Private Declare Function EmptyClipboard Lib "user32" () As Long
Private Declare Function RegisterClipboardFormat Lib "user32" Alias _
"RegisterClipboardFormatA" (ByVal lpString As String) As Long
Private Declare Function GlobalLock Lib "kernel32" (ByVal hMem As Long) _
As Long
Private Declare Function GlobalUnlock Lib "kernel32" ( _
ByVal hMem As Long) As Long
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" ( _
pDest As Any, pSource As Any, ByVal cbLength As Long)
Private Declare Function GetClipboardData Lib "user32" ( _
ByVal wFormat As Long) As Long
Private Declare Function lstrlen Lib "kernel32" Alias "lstrlenA" ( _
ByVal lpData As Long) As Long
Private Const m_sDescription = _
"Version:1.0" & vbCrLf & _
"StartHTML:aaaaaaaaaa" & vbCrLf & _
"EndHTML:bbbbbbbbbb" & vbCrLf & _
"StartFragment:cccccccccc" & vbCrLf & _
"EndFragment:dddddddddd" & vbCrLf
Private m_cfHTMLClipFormat As Long
Function RegisterCF() As Long
'Register the HTML clipboard format
If (m_cfHTMLClipFormat = 0) Then
m_cfHTMLClipFormat = RegisterClipboardFormat("HTML Format")
End If
RegisterCF = m_cfHTMLClipFormat
End Function
Public Sub PutHTMLClipboard(sHtmlFragment As String, _
Optional sContextStart As String = "<HTML><BODY>", _
Optional sContextEnd As String = "</BODY></HTML>")
Dim sData As String
If RegisterCF = 0 Then Exit Sub
'Add the starting and ending tags for the HTML fragment
sContextStart = sContextStart & "<!--StartFragment -->"
sContextEnd = "<!--EndFragment -->" & sContextEnd
'Build the HTML given the description, the fragment and the context.
'And, replace the offset place holders in the description with values
'for the offsets of StartHMTL, EndHTML, StartFragment and EndFragment.
sData = m_sDescription & sContextStart & sHtmlFragment & sContextEnd
sData = Replace(sData, "aaaaaaaaaa", _
Format(Len(m_sDescription), "0000000000"))
sData = Replace(sData, "bbbbbbbbbb", Format(Len(sData), "0000000000"))
sData = Replace(sData, "cccccccccc", Format(Len(m_sDescription & _
sContextStart), "0000000000"))
sData = Replace(sData, "dddddddddd", Format(Len(m_sDescription & _
sContextStart & sHtmlFragment), "0000000000"))
'Add the HTML code to the clipboard
If CBool(OpenClipboard(0)) Then
Dim hMemHandle As Long, lpData As Long
hMemHandle = GlobalAlloc(0, Len(sData) + 10)
If CBool(hMemHandle) Then
lpData = GlobalLock(hMemHandle)
If lpData <> 0 Then
CopyMemory ByVal lpData, ByVal sData, Len(sData)
GlobalUnlock hMemHandle
EmptyClipboard
SetClipboardData m_cfHTMLClipFormat, hMemHandle
End If
End If
Call CloseClipboard
End If
End Sub
Public Function GetHTMLClipboard() As String
Dim sData As String
If RegisterCF = 0 Then Exit Function
If CBool(OpenClipboard(0)) Then
Dim hMemHandle As Long, lpData As Long
Dim nClipSize As Long
GlobalUnlock hMemHandle
'Retrieve the data from the clipboard
hMemHandle = GetClipboardData(m_cfHTMLClipFormat)
If CBool(hMemHandle) Then
lpData = GlobalLock(hMemHandle)
If lpData <> 0 Then
nClipSize = lstrlen(lpData)
sData = String(nClipSize + 10, 0)
Call CopyMemory(ByVal sData, ByVal lpData, nClipSize)
Dim nStartFrag As Long, nEndFrag As Long
Dim nIndx As Long
'If StartFragment appears in the data's description,
'then retrieve the offset specified in the description
'for the start of the fragment. Likewise, if EndFragment
'appears in the description, then retrieve the
'corresponding offset.
nIndx = InStr(sData, "StartFragment:")
If nIndx Then
nStartFrag = CLng(Mid(sData, _
nIndx + Len("StartFragment:"), 10))
End If
nIndx = InStr(sData, "EndFragment:")
If nIndx Then
nEndFrag = CLng(Mid(sData, nIndx + Len("EndFragment:"), 10))
End If
'Return the fragment given the starting and ending
'offsets
If (nStartFrag > 0 And nEndFrag > 0) Then
GetHTMLClipboard = Mid(sData, nStartFrag + 1, _
(nEndFrag - nStartFrag))
End If
End If
End If
Call CloseClipboard
End If
End Function
Add the following code in the code window for Form1:
Private Sub Command1_Click()
Dim sFrag As String, sStart As String, sEnd As String
sStart = "<HTML><BODY><FONT FACE=Arial SIZE=1 COLOR=BLUE>"
sFrag = "<B>This is bold</B> and <I>this is italic.</I>"
sEnd = "</FONT></BODY></HTML>"
PutHTMLClipboard sFrag, sStart, sEnd
End Sub
Private Sub Command2_Click()
MsgBox GetHTMLClipboard
End Sub
Press the F5 key to start the Visual Basic program. Click Put HTML to add the HTML data to the clipboard. Then, click Get HTML to retrieve the clipboard data. Note that a message box displays
the HTML fragment.
Start Microsoft Word (or any application that recognizes
the HTML Format for the clipboard). Paste the clipboard contents to a new
document to examine the results of the HTML code contained on the
clipboard.
Additional note
Using an approach that sends HTML code to the clipboard might be
especially beneficial for Office Automation clients. For example, if you have
an Automation client that needs to generate formatted data for cells in
Microsoft Excel or paragraphs in Microsoft Word, you could build the data in
HTML code, send it to the clipboard, and then paste it into the application. By
using this technique, you could reduce the number of out-of-process calls to
the Automation client.
To learn more about the specifics of the HTML clipboard
format, see the topic "HTML Clipboard Format" at the following Microsoft Developer
Network (MSDN) Web site:
Back to the top
