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Clipboard backup (Visual C++)

sswater shi

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4.58/5 (24 votes)

20 Sep 2005CPOL

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Make a backup copy of clipboard data before your clipboard operation, and when you finish, you can restore clipboard to its original status.

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();

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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)

Written By

sswater shi

Software Developer (Senior)

China

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/

Comments and Discussions

Re: How to do it in c#

sswater shi13-Oct-05 16:21

13-Oct-05 16:21

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)!

Re: How to do it in c#

nagarsoft13-Oct-05 20:01

13-Oct-05 20:01

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 shi13-Oct-05 20:47

13-Oct-05 20:47

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#

nagarsoft14-Oct-05 6:19

14-Oct-05 6:19

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

<br />
IDataObject oldClipboard = Clipboard.GetDataObject();<br />
DataObject newClipboard = new DataObject();<br />
string[] s;<br />
s = oldClipboard.GetFormats(); //gets all the possible formats for that data<br />
<br />
foreach(string ns in s) {<br />
   newClipboard.SetData(ns,oldClipboard.GetData(ns)); //re-associate the old data with the proper types<br />
}<br />
<br />
//this is where your clipboard manipulation goes.<br />
Clipboard.SetDataObject(newClipboard,true); //true makes sure the data persists<br />

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!

vkurdukov20-Sep-05 1:43

20-Sep-05 1:43

A small notion: may be it is worth to have
#include "ClipboardBackup.h"<>
in ClipboardBackup.cpp

Re: Very useful class - thanks a lot!

sswater shi20-Sep-05 16:45

20-Sep-05 16:45

Thank you for your notion, I have updated the zip file Smile | :)

Smile | :)

#include <afxtempl.h> is needed.

sswater shi23-Aug-05 15:56

23-Aug-05 15:56

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 ------

Re: #include <afxtempl.h> is needed.

lxdff23-Aug-05 16:25

23-Aug-05 16:25

Very Good!

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