event Changing (InputFile as String, Cancel as Variant)
Occurs when the thumbnail view is changing.

TypeDescription
InputFile as String A String expression that specifies the file to be previewed.
Cancel as Variant A Boolean expression that specifies whether the operation is performed or canceled. By default, the Cancel parameter is False, which means the operation is going to be performed.
The control fires the Changing event just before previewing the giving file. In other words, the Changing event is fired when the user drags a file over the control, so you can specify whether to accept or not the file. The control fires the Change event when the previewing is done. Use the Thumbnail property to specify whether the control has a thumbnail view loaded. Change the Cancel parameter to True, if you need to cancel dropping the file. The InputFile property specifies the file being previewed.

The following VB sample prompts whether to accept or reject previewing the dropped file:

Private Sub Thumbnail1_Changing(ByVal Path As String, Cancel As Variant)
    Cancel = MsgBox("Do you want to preview the " & Path, vbYesNo) = vbNo
End Sub
  

Syntax for Changing event, /NET version, on:

private void Changing(object sender,string InputFile,ref object Cancel)
{
}

Private Sub Changing(ByVal sender As System.Object,ByVal InputFile As String,ByRef Cancel As Object) Handles Changing
End Sub

Syntax for Changing event, /COM version, on:

private void Changing(object sender, AxEXTHUMBNAILLib._IThumbnailEvents_ChangingEvent e)
{
}

void OnChanging(LPCTSTR InputFile,VARIANT FAR* Cancel)
{
}

void __fastcall Changing(TObject *Sender,BSTR InputFile,Variant * Cancel)
{
}

procedure Changing(ASender: TObject; InputFile : WideString;var Cancel : OleVariant);
begin
end;

procedure Changing(sender: System.Object; e: AxEXTHUMBNAILLib._IThumbnailEvents_ChangingEvent);
begin
end;

begin event Changing(string InputFile,any Cancel)
end event Changing

Private Sub Changing(ByVal sender As System.Object, ByVal e As AxEXTHUMBNAILLib._IThumbnailEvents_ChangingEvent) Handles Changing
End Sub

Private Sub Changing(ByVal InputFile As String,Cancel As Variant)
End Sub

Private Sub Changing(ByVal InputFile As String,Cancel As Variant)
End Sub

LPARAMETERS InputFile,Cancel

PROCEDURE OnChanging(oThumbnail,InputFile,Cancel)
RETURN

Syntax for Changing event, /COM version (others), on:

<SCRIPT EVENT="Changing(InputFile,Cancel)" LANGUAGE="JScript">
</SCRIPT>

<SCRIPT LANGUAGE="VBScript">
Function Changing(InputFile,Cancel)
End Function
</SCRIPT>

Procedure OnComChanging String llInputFile Variant llCancel
	Forward Send OnComChanging llInputFile llCancel
End_Procedure

METHOD OCX_Changing(InputFile,Cancel) CLASS MainDialog
RETURN NIL

void onEvent_Changing(str _InputFile,COMVariant /*variant*/ _Cancel)
{
}

function Changing as v (InputFile as C,Cancel as A)
end function

function nativeObject_Changing(InputFile,Cancel)
return