Client side removeHandler error

[JiriSchmitt]

Hello,

I have own composite control inherited from RadWebControl. It contains RadTextBox control where I need handle keyup client event.
I have implemented client class for it and I attached event in initialize function. In dispose function I'm removing this event handler but it causes javascript error:

Line: 6
Error: '_events' is null or not an object

Here is the script:

nData.KnowledgeManagement.Web.UI.Searcher.prototype =
{
    initialize: function () {
        nData.KnowledgeManagement.Web.UI.Searcher.callBaseMethod(this, 'initialize');

        // SearchTextBox
        this._searchTextBox = $find(this.get_id() + '_searchTextBox');
        this._keyUpDelegate = Function.createDelegate(this, this._keyUp);
        $addHandler(this._searchTextBox._textBoxElement, "keyup", this._keyUpDelegate);

        // XmlHttpPanel
        this._xmlHttpPanel = $find(this.get_id() + '_xmlHttpPanel');
        this._xmlHttpPanel._searcher = this;
        this._xmlHttpPanel.add_responseEnding(this._xmlHttpPanelResponseEnding);
        this._xmlHttpPanel.add_responseError(this._clientResponseError);
    },

    dispose: function () {
        nData.KnowledgeManagement.Web.UI.Searcher.callBaseMethod(this, 'dispose');

        if (this._keyUpDelegate) {
            $removeHandler(this._searchTextBox._textBoxElement, "keyup", this._keyUpDelegate);
            this._keyUpDelegate = null;
        }

        this._xmlHttpPanel.remove_responseEnding(this._xmlHttpPanelResponseEnding);
        this._xmlHttpPanel.remove_responseError(this._clientResponseError);
    },

    _keyUp: function () {
        this._search(this._searchTextBox._textBoxElement.value);
    },
    ...
}

Cound you tell me what I have wrong?
Thanks
Jiri

[Maria Ilieva]

Hello Jiri,

I would suggest you to revise the following online resources:
http://forums.asp.net/t/1315438.aspx
http://stackoverflow.com/questions/3893621/events-is-null-or-not-an-object-error-only-when-compilation-debug-false
http://www.tek-tips.com/viewthread.cfm?qid=940870

Also note that we do not support inheriting from base RadControl.

Kind regards,
Maria Ilieva
the Telerik team

[JiriSchmitt]

Hello Maria,

thanks for reply. I found that problem is because dispose method on SearchTextBox (RadTextBox) control is called before dispose method on my parent control.
And RadInputControl finishing with "this._textBoxElement._events = null;" code, which causes error during call $removeHandler from my parent control.

So maybe there is better way how to register/unregister handler on RadTextBox control. I need hande keyup event.
Is there something for it? I tried add_keyPress but it is not fire for all changes in textbox.

I need something like:

this._searchTextBox.add_keyUp(this._keyUp);
  ...
this._searchTextBox.remove_keyUp(this._keyUp);

Thank you
Jiri

[JiriSchmitt]

I got answer in my supprot ticket:
--------------------------------------

Regarding the issue with removing the handler, the $addHandler method accepts fourth Boolean argument, that shows whether the handler should be automatically removed when the element is disposed, so I would recommending passing true, and you would not need to remove it explicitly. This is the way I have done it in your project.

[Maria Ilieva]

Hello Jiri,

I'm glad that the solution provided by my colleague helps you fix the problem. Let us know if further assistance is need.


Best wishes,
Maria Ilieva
the Telerik team