How can I copy something to the Clipboard without it showing up in the history?

When I copy something onto the clipboard, it shows up in the Clipboard history (Win+V). And with Windows 10 and Windows 11, it also syncs the clipboard with the cloud and other devices.

When I copy sensitive data onto the clipboard (like a password), I don't want it to show up in the history, and I don't want Windows to sync it to other devices.

How can I manage to do that?

You can not only put Text on the clipboard, but all kind of different types of data. It's like a Multi-Part-Message in an EMail, where you can have the mail in plain text and in HTML format.

There are many default Clipboard types that are known to Delphi. And on Windows 10 and later, the Cloud Clipboard has 3 new Clipboard types that are not represented by ID but per Name, such as "ExcludeClipboardContentFromMonitorProcessing":

https://learn.microsoft.com/en-us/windows/win32/dataxchg/clipboard-formats

You have to declare these 3 new types yourself and set them if you copy sensitive data.

I wrote a TClipboard helper so it is easier to handle. It adds a SetTextWithoutHistory() method.

Here is the helper:

unit vcl.Clipbrd.sec;

interface

uses
  Windows, Clipbrd, SysUtils;


type
  TClipboardSec = class helper for TClipboard
  public
    procedure SetTextWithoutHistory(const Value: string);
    property AsTextWithoutHistory : string write SetTextWithoutHistory;
  end;


implementation

var
  dwNo : DWORD;
  dwYes: DWORD;
  CF_ExcludeClipboardContentFromMonitorProcessing : UINT;
  CF_CanIncludeInClipboardHistory: UINT;
  CF_CanUploadToCloudClipboard: UINT;

procedure TClipboardSec.SetTextWithoutHistory(const Value: string);
begin
  Open;
  try
    Adding;

    SetBuffer(CF_ExcludeClipboardContentFromMonitorProcessing, dwYes, sizeOf(DWORD) );
    SetBuffer(CF_CanIncludeInClipboardHistory, dwNo, sizeOf(DWORD) );
    SetBuffer(CF_CanUploadToCloudClipboard, dwNo, sizeOf(DWORD));

    SetBuffer(CF_UNICODETEXT, PChar(Value)^, ByteLength(Value) + SizeOf(Char));
  finally
    Close;
  end;

end;


initialization
  dwNo  := 0;
  dwYes := 1;

  CF_ExcludeClipboardContentFromMonitorProcessing := RegisterClipboardFormat('ExcludeClipboardContentFromMonitorProcessing');
  if CF_ExcludeClipboardContentFromMonitorProcessing = 0
    then RaiseLastOSError;

  CF_CanIncludeInClipboardHistory := RegisterClipboardFormat('CanIncludeInClipboardHistory');
  if CF_CanIncludeInClipboardHistory = 0
    then RaiseLastOSError;

  CF_CanUploadToCloudClipboard := RegisterClipboardFormat('CanUploadToCloudClipboard');
  if CF_CanUploadToCloudClipboard = 0
    then RaiseLastOSError;
finalization
end.

I hope it helps someone.

I needed a long time to figure it out.