Hi,

I'm trying to build my own TFileComboBox component and I'm still new to component development.  Can someone please provide an idea why this will not bind when I try to add it and rebuild the component library?  

{$IFNDEF BROWSER}
uses WebCore, WebUI;
{$ELSE}
uses WebDOM, WebCore, WebHTTP, WebUI;
{$ENDIF}

type
  {$IFNDEF BROWSER}
  external TFileInputElementExtended = class(TFileInputElement)
     public
        property AcceptTypes: String read write;
        procedure Click;
     end;

  {$ELSE}
  TFileInputElementExtended = class(TFileInputElement)
     protected
        function CreateDOMElement: THTMLElement; override;
     end;
  {$ENDIF}

There errors are:

Cannot bind to external class type TFileInputElementExtended
Cannot bind to external property AcceptTypes
Cannot bind to external method Click

Thank you!

Best regards,
Allen

Allen Hunt wrote:

> Can someone please provide an idea why this will not bind when I try to add it and rebuild the component library?  

I've managed to stumble past the issue but I don't have a permanent answer yet.  It's an IFDEF problem.  I'm trying to understand these in the help file and how it relates to the way the component library is built:

DESIGN Indicates that the code is being compiled for execution in the IDE
BROWSER Indicates that the code is being compiled for execution in a client application
RUNTIME Indicates that the code is being compiled for execution in a server application
CLIENT Indicates that the code is being compiled for client usage
SERVER Indicates that the code is being compiled for server usage
VERNNN Indicates the major/minor version of the Elevate Web Builder compiler, where NNN is the major/minor version number (without the period between the major and minor versions)

I'll do my best to post a solution if I figure it out.  Thank you!

Best regards,
Allen

On 10/28/2022 7:17 AM, Allen Hunt wrote:
> Hi,
>
> I'm trying to build my own TFileComboBox component and I'm still new to component development.  Can someone please provide an idea why this will not bind when I try to add it and rebuild the component library?

This is just observation based on a super quick look so might be totally
wrong.

I don't believe TFileInputElement is itself a IDE component. It is a UI
element but not a component and does not implement many of the component
"things" - interface, GetInterfaceClassName, InitializeProperties etc

I'd suggest try to start with something that is UI component already and
go from there - basically go to library tab and do "new component" and
see if anything in the "ancestor component" list would be a good base.
If nothing else just a TComponent. And then you can use elements as UI
parts of the component.

Raul

Raul wrote:

On 10/28/2022 7:17 AM:

Thank you Raul!  Yea I'm still trying to grasp it.  I don't have a clear picture of GetInterfaceClassName, InitializeProperties, or even the InterfaceManager.RegisterElementClass.  Thank you for reminding me about the new component feature.  That did help.

It turns out I didn't even need the external TFileInputElement.  All I had to do was:

{$IFNDEF BROWSER}
uses WebCore, WebUI, WebCtrls, WebEdits;
{$ELSE}
uses WebDOM, WebCore, WebHTTP, WebUI, WebCtrls, WebEdits;
{$ENDIF}

type

     {$IFDEF BROWSER}
     TFileInputElementExtended = class(TInputElement)
        private
           FMultiple: Boolean;
           FChangeHandler: TEventHandler;
           function GetAcceptTypes: String;
           procedure SetAcceptTypes(const Value: String);
        protected
           function CreateDOMElement: THTMLElement; override;
           procedure SetDOMEventHandlers; override;
           procedure ClearDOMEventHandlers; override;
           procedure Update(AChanges: TSet; AInitialize: Boolean=False); override;
           procedure DoChange; virtual;
        public
           property AcceptTypes: String read GetAcceptTypes write SetAcceptTypes;
           procedure Click;
        end;
  {$ENDIF}

implementation

{$IFDEF BROWSER}
...
{$ENDIF}

I modified TFileComboBox's component FInputElement: TFileInputElement to allow for multiple files to be uploaded.  Here's a code snippet:

HTML_ATTR_MULTIPLE = 'multiple'

function TFileInputElement.CreateDOMElement: THTMLElement;
begin
  Result:=inherited CreateDOMElement;
  Result.setAttribute(HTML_ATTR_TYPE,HTML_VALUE_FILE);

  Result.setAttribute('multiple','');    // or Result.setAttribute(HTML_ATTR_MULTIPLE,'');  <--- add this right here
end;

Trying to understand all the different cycles the compiler appears to be going through when adding a component to the library, rebuilding the library, etc. is a task! Thank you so much!

Best regards,
Allen

Allen would you upload your Multiple File Upload component to the EWB components section of the forum?

Walter Matte wrote:

>  Allen would you upload your Multiple File Upload component to the EWB components section of the forum?

Sure!  I'm not done but I posted what I had.  I don't understand why InterfaceManager.RegisterElementClass( TFileInputElementExtended, HTML_TAG_INPUT ); in the InitializeProperties appears to be needed but it seems to be working for me now.  There is probably a correct answer somewhere.

I made RegisterElementClass public in the WebUI which I'm sure Tim will probably say is a no no.

As I learn more, I let you know!

Best regards,
Allen