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21 votes for this article.

Popularity: 5.63 Rating: 4.26 out of 5

Download source files - 1.47 Kb

Introduction

This piece of code is to help you backup your clipboard data and restore it after you have finished other clipboard operations.

My experience: while I'm developing Word add-in programs, the icon of the new-added button can only be set through clipboard by "...->PasteFace()". This will empty the clipboard data which is going to be pasted in Word. So, I wrote this class, and it helped me a lot.

Usage:

  // the constructor will do backup clipboard operation

  CClipboardBackup cbbackup;
 
  // any other clipboard operations

  ::OpenClipboard(NULL);
  ::EmptyClipboard();
  ::SetClipboardData(......);
  ::CloseClipboard();
  ....
 
  // restore

  cbbackup.Restore();

By the way, my another article about another topic on another website :) :

How to use GRETA Regular Expression in Visual C++ correctly.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

About the Author

sswater shi

Member

Begin coding from basic, since 1994. Interested in coding and database and website constructing.
My website: http://www.regexlab.com/ - Regular Expression Laboratory
The easiest regex engine: http://www.regexlab.com/deelx/

Occupation:	Software Developer
Location:	China

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Msgs 1 to 22 of 22 (Total in Forum: 22) (Refresh)

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Problem with CF_BITMAP

MohammadAmiry

14:06 28 Mar '07

Hi and thank you for your great and helpful article! If the clipboard contains BITMAP, `GetClipboardFormatName` deos not fill data.m_szFormatName and also `HANDLE hMem = ::GetClipboardData( format );` Makes hMem=0 This happens only to BITMAPs and works perfect on nther formats I checked. I need to have bitmaps saved too. I'd be really greatfull if you help me out with this.
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Re: Problem with CF_BITMAP

sswater shi

15:36 28 Mar '07

HBITMAP and HMETAFILE may have similar problems. In fact, if we saved CF_DIB, we need not save CF_BITMAP. The system will transform CF_DIB into CF_BITMAP. I have made a small change on 'CClipboardBackup' and I have used it in another project: http://www.codeproject.com/com/wordhighlight.asp[^] Take another try on the 'CClipboardBackup' in 'Wordhighlight' project.
Sign In·View Thread·PermaLink	3.00/5 (1 vote)

problem with outlook

vice

7:53 12 Feb '07

hi, first thanks for this class. but i have a problem in combination with outlook and only i a special case. if you copy an attachment of a mail in the clipboard and paste it in a new email, it doesn't work if your backup and restore function is called between the copy and paste. ( it also not work if you paste the attachment somewhere else... ) perhaps anyone has an idear? thanks Thomas R.
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Re: problem with outlook

sswater shi

2:58 13 Feb '07

Thanks for your comment.

Some clipboard formats may be different from others. Maybe I have not deal those special formats in the right way. Please refer to this link:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/dataexchange/clipboard/clipboardoperations.asp[^]

I have made a small change on this class, and I have used it in another article:

http://www.codeproject.com/com/wordhighlight.asp[^]

You can try the 'ClipboardBackup' in the 'WordSyntax' add-in.

Reply this message again if any questions.

Re: problem with outlook

vice

3:52 13 Feb '07

Hello again, your Word-Addin has the same bug but you use the backup and restore of the clipboard very seldom. so the bug only apears if your toolbar is created at the first time. I will look if i can find a solution. Thanks for your help.
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Re: problem with outlook

sswater shi

22:57 13 Feb '07

Maybe, when outlook is copying file between email and new email, it used 'provides data upon request'.

When 'SetClipboardData', if the data is 'NULL', it indicates that the window provides data in the specified clipboard format (renders the format) upon request. When 'paste', the owner window of the clipboard will be informed to provide data.

I have not found a way to backup the whole clipboard status completely. If the clipboard data is backuped and restored once, the owner window of the clipboard will be changed.

Maybe, this is the reason. I'm not so sure.

5.00/5 (1 vote)

Great ! + possible error

ChrisRibe

9:37 22 Mar '06

Nice class thanks.

I was looking at the problem and thinking gee this should be easy to do. But when I realized all the different formats that can be copied I was stuck asking myself "how should I do this?" and "this is harder than I thought". So thanks for the help.

Also I think you are missing an unlock in the Backup() method no?

----------- Snip -----------

LPVOID pMem = ::GlobalLock( hMem );
data.m_pData = new byte[data.m_nLength];

memcpy(data.m_pData, pMem, data.m_nLength);

//HERE you need to add this no? --> ::GlobalUnlock( hMem );

m_lstData.AddTail(data);

----------- Snip end -----------

Chris Smile

Re: Great ! + possible error

sswater shi

14:39 22 Mar '06

Thank you very much for your patience on the problem. Yes, I missed an unlock indeed. This class may has other problems too. I am not so sure how to deal with formats such as CF_ENHMETAFILE. Your can refer to former comment "CF_ENHMETAFILE" by Mr FlyZu and the replies. Thanks again.
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IE Access violation for CF_BITMAP

jnettleton

7:56 2 Dec '05

When I copied at bitmap image from an IE browser window, my Word COM add-in tried to save the clipboard and encountered an access violation. Any ideas?

Thanks, Jerry

Here's the debug output:

CLIPBOARD FORMAT: 0xC009, DataObject
CLIPBOARD FORMAT: 0xC2EC, UntrustedDragDrop
CLIPBOARD FORMAT: 15
CLIPBOARD FORMAT: 8
CLIPBOARD FORMAT: 0xC0CE, HTML Format
CLIPBOARD FORMAT: 0xC013, Ole Private Data
CLIPBOARD FORMAT: 2
First-chance exception at 0x77f9cec6 (ntdll.dll) in WINWORD.EXE: 0xC0000005: Access violation reading location 0x50050d4f.

1.00/5 (1 vote)

Re: IE Access violation for CF_BITMAP

sswater shi

22:00 3 Dec '05

When I was writing my code, I simplely regard each type of clipboard data as a memory block, and I simplely use GlobalAlloc to allocate memory space. But this is not right in many cases:

I'm very sorry that my mistake may have misguided you. Special functions should be used to operate many type of clipboard data.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/dataexchange/clipboard/clipboardoperations.asp[^]

CF_BITMAP maybe should not be operated by GlobalLock etc, I think, but I'm not very sure.

CF_ENHMETAFILE

FlyZu

3:23 10 Nov '05

Thanks a lot for your code. It helped me a lot. But, there is a problem. It's not possible to restore the data of type CF_ENHMETAFILE. I think it's because we have to create meta files to store the data and after that, we can restore it. I dont' know how to do this. It would be nice if you can have a look to this problem. Or if you have any hints, don't hesitate.
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Re: CF_ENHMETAFILE

sswater shi

16:57 13 Nov '05

Thank you for your question!
In my code, I simplely regard each type of clipboard data as a memory block, and I simplely use GlobalAlloc to allocate memory space. But this is not right in certain cases.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/dataexchange/clipboard/clipboardoperations.asp[^]

Indeed, CF_ENHMETAFILE should be created by CopyMetaFile or CreateMetaFile. Not all the formats could be regarded as simple memory block.
(I'm sorry I have just known this too, after I have just found it in MSDN)

3.50/5 (2 votes)

Re: CF_ENHMETAFILE

FlyZu

0:00 14 Nov '05

Don't be sorry.

I think I've found a possible solution. I added a field of type HENHMETAFILE in the structure.

Backup :
When the format is of type CF_ENHMETAFILE, I simply save the metafile like this : data.metafile = CopyEnhMetaFile((HENHMETAFILE)GetClipboardData(data.format))

Restore :
To restore the clipboard, if the format is equal to CF_ENHMETAFILE, I do a SetClipboard(data.format, data.metafile).

It works fine. Wink

-- modified at 5:39 Monday 14th November, 2005

How to do it in c#

nagarsoft

12:49 13 Oct '05

Hi, is there a way to do it in C#? Do I have to know the data type currently present into the clipboard? Can I make it completely generic? Thanks a lot. Andrea
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Re: How to do it in c#

sswater shi

17:21 13 Oct '05

Windows api can be invoked in C#, so clipboard backup can be implemented. The following apis are needed:

class Win32ClipboardAPI
{
      [DllImport("user32.dll")]
      public static extern bool OpenClipboard(IntPtr hWndNewOwner);

      [DllImport("user32.dll")]
      public static extern bool EmptyClipboard();

      [DllImport("user32.dll")]
      static extern IntPtr GetClipboardData(uint uFormat);

      [DllImport("user32.dll")]
      public static extern IntPtr SetClipboardData(uint uFormat, IntPtr hMem);

      [DllImport("user32.dll")]
      public static extern bool CloseClipboard();

      [DllImport("user32.dll")]
      static extern uint EnumClipboardFormats(uint format);

      [DllImport("user32.dll")]
      static extern int GetClipboardFormatName(uint format, [Out] StringBuilder lpszFormatName, int cchMaxCount);

      [DllImport("user32.dll", SetLastError=true)]
      static extern uint RegisterClipboardFormat(string lpszFormat);
}

class Win32MemoryAPI
{
      [DllImport("Kernel32.dll", EntryPoint="RtlMoveMemory", SetLastError=false)]
      public static extern void CopyMemory(IntPtr dest, IntPtr src, int size);

      [DllImport("kernel32.dll")]
      public static extern IntPtr GlobalAlloc(uint uFlags, UIntPtr dwBytes);

      [DllImport("kernel32.dll")]
      public static extern IntPtr GlobalLock(IntPtr hMem);

      [DllImport("kernel32.dll")]
      public static extern IntPtr GlobalFree(IntPtr hMem);

      [DllImport("kernel32.dll")]
      public static extern UIntPtr GlobalSize(IntPtr hMem);

      public const uint GMEM_DDESHARE = 0x2000;
      public const uint GMEM_MOVEABLE = 0x2;
}

you can rewrite my class CClipboardBackup into C# with these apis.

Good luck! Write to me if you need help (sswater@gmail.com)!

1.00/5 (2 votes)

Re: How to do it in c#

nagarsoft

21:01 13 Oct '05

Thanks for your help. I'll give it a try. I thought there was a solution not involving PInvoke. Actually, .NET has a clipboard class with two methods GetData and Setdata.

I was using the following code

//backup original data
IDataObject data=Clipboard.GetDataObject();

//insert new data into the clipboard
string test="test data";
Clipboard.SetDataObject(test);

//restore old data
Clipboard.SetDataObject(data);

but I get an exception (or no data is restored) when I call the last function.
I think the problem has to do with the first instruction where I save the data. Do I have to necessarily know the format of the data into the clipboard? Can't I just do a snapshot of it and restore it into place later?
Thanks a lot.

Re: How to do it in c#

sswater shi

21:47 13 Oct '05

I have never used class Clipboard in .NET before, so I'm sorry and I could not give you a complete explanation.

I read the MSDN just now, I thought that the SetDataObject (in .NET) could only set one data of one certain format. After my glance at MSDN, I have not find a way to set datas of more than one format.

In my C++ implementation, I regard each clipboard format data as binary data and make a backup copy for each.

Re: How to do it in c#

nagarsoft

7:19 14 Oct '05

I've found how to do it in C# and would like to share the solution.
Here's the code.


IDataObject oldClipboard = Clipboard.GetDataObject();
DataObject newClipboard = new DataObject();
string[] s;
s = oldClipboard.GetFormats(); //gets all the possible formats for that data

foreach(string ns in s) {
   newClipboard.SetData(ns,oldClipboard.GetData(ns)); //re-associate the old data with the proper types
}

//this is where your clipboard manipulation goes.
Clipboard.SetDataObject(newClipboard,true); //true makes sure the data persists

and here's the link where I found it. Hope other people will find it useful.

http://objectsharp.com/blogs/dan/archive/2004/08/20/836.aspx[^]

Very useful class - thanks a lot!

vkurdukov

2:43 20 Sep '05

A small notion: may be it is worth to have `#include "ClipboardBackup.h"<>` in ClipboardBackup.cpp
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Re: Very useful class - thanks a lot!

sswater shi

17:45 20 Sep '05

Thank you for your notion, I have updated the zip file
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#include <afxtempl.h> is needed.

sswater shi

16:56 23 Aug '05

I have used afx template class 'CList', so #include <afxtempl.h> is needed. To add this line in your stdafx.h is better than other places. ----- posted by myself ------
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Re: #include <afxtempl.h> is needed.

lxdff

17:25 23 Aug '05

Very Good! Attitude is anything
Sign In·View Thread·PermaLink	2.43/5 (3 votes)

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Clipboard backup (Visual C++)

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