Getting Clipboard Handle using GetClipboardData in C#

[Roohi]

hi

I am trying to copy an image to a clipboard and then get a
handle to the clipboard using API calls GetClipboardData().

Following is the snippet of our code. Could any one please
point out what am I missing here since I never get the
handle to the object on clipboard

<snippet>

OpenClipboard(0);

DataObject m_data = new DataObject();

m_data.SetData(DataFormats.Dib,imgCardImage.Image);

Clipboard.SetDataObject(m_data,false);

hDib = GetClipboardData(CF_DIB); // CF_DIB = 8;

</snippet>


hDib returned is always 0 where it actually had to return
a handle to the clipboard;

Thanks in Advance.

~Roohi

 

[Morten Wennevik]

Not familiar with GetClipboardData.
Why do you need a handle to it instead of using .NET's
ClipBoard.GetDataObject to retrieve it?

 

[Roohi]

I need to pass this handle to some other API which accepts
handle to the clipboard as a parameter

Hence I need it

Thanks

 

[Morten Wennevik]

Hm, maybe Clipboard.SetDataObject() closes the clipboard you opened with
OpenClipboard().
Try moving OpenClipBoard(0); after SetDataObject()

 

[Roohi]

I tried doing that, but still the same problem

Roohi

 

[Jeff Gaines]

hi

I am trying to copy an image to a clipboard and then get a
handle to the clipboard using API calls GetClipboardData().

~Roohi

Roohi

Can you modify this to do what you need:

public static bool JCopyFilesToClipboard(string[] strFiles, POINT pt)
{
bool blnReturn = false;
byte[] bData;
DROPFILES df = new DROPFILES();
int intChar, intFile, intDataLen, intPos;
IntPtr ipGlobal = IntPtr.Zero;

// Calculate total data length
intDataLen = 0;
for(intFile = 0; intFile <= strFiles.GetUpperBound(0);
intFile++)
intDataLen += strFiles[intFile].Length + 1;

// Terminating double zero
intDataLen++;

bData = new Byte[intDataLen];
intPos = 0;

// Build null terminated list of files
for(intFile = 0; intFile <= strFiles.GetUpperBound(0);
intFile++)
{
for(intChar = 0; intChar < strFiles[intFile].Length;
intChar++)
{
bData[intPos++] = (byte)strFiles[intFile][intChar];
}
bData[intPos++] = 0;
}
// Terminating double zero
bData[intPos++] = 0;

// Allocate and get pointer to global memory
int intTotalLen = Marshal.SizeOf(df) + intDataLen;
ipGlobal = Marshal.AllocHGlobal(intTotalLen);

if(ipGlobal == IntPtr.Zero)
return false;

// Build DROPFILES structure in global memory.
df.pFiles = Marshal.SizeOf(df);
df.pt = pt;
df.fNC = false;
df.fWide = 0;
Marshal.StructureToPtr(df, ipGlobal, true);
IntPtr ipNew = new IntPtr(ipGlobal.ToInt32() +
Marshal.SizeOf(df));
Marshal.Copy(bData, 0, ipNew, intDataLen);

// Open and empty clipboard
if(!OpenClipboard(IntPtr.Zero))
return false;

EmptyClipboard();

// Copy data to clipboard
blnReturn = (SetClipboardData(CF_HDROP, ipGlobal) !=
IntPtr.Zero);
if(!blnReturn)
Marshal.FreeHGlobal(ipGlobal);

// Clean up
CloseClipboard();
// Clipboard responsible for freeing memory
// Marshal.FreeHGlobal(ipGlobal);

return blnReturn;
}

It's a different file format but the principle is similar.

 

[Jeff Gaines]

hi

I am trying to copy an image to a clipboard and then get a
handle to the clipboard using API calls GetClipboardData().

Following is the snippet of our code. Could any one please
point out what am I missing here since I never get the
handle to the object on clipboard


hDib returned is always 0 where it actually had to return
a handle to the clipboard;

Thanks in Advance.

~Roohi

Roohi

I am not sure now if my earlier post answers your question :-(

I have tried what you are doing - you must call open clipboard before
trying to get the handle to the data. Is the clipboard still open when
you make this call or have you already closed it?