6 Answers, 1 is accepted
Please review our online example Server Events.
Kind regards,
Rosi
the Telerik team
Check out Telerik Trainer, the state of the art learning tool for Telerik products.
Rank 2
I know how to filter keys on the TextChanged Event in order to get if it was the entery key.
now my particular issue:
I am creating a User Control which contains a RadComboBox Loadable on Demand which fills data from a webService. Everything is ok here.
I need to trigger a server event when the user presses the enter button. The problem here is that I need to invoke an event to the aspx page, not the ascx. Everything is ok here too :) (thanks to this)
Now the problem is that this event generates too many Post-backs, I would like to somehow control the TextChanged event from the Client side and if the key pressed was the "enter" key, then trigger the server-side event. Is this possible?
in Advance, many thanks :)
Rank 1
I would like to support the ideas of Gabriel. Here my thoughts:
- RadTextBox has ClientEvents, I use it as follows
<telerik:RadTextBox Visible="false" ID="RadTextBox1" Width="270px" runat="server"
CssClass="NormalTextBox" AutoPostBack="True" BorderStyle="Solid" BorderColor="Gainsboro"
Font-Names="Verdana">
<ClientEvents OnKeyPress="HandleEnterKeyPress" />
</telerik:RadTextBox>
and
<script type="text/javascript">
function HandleEnterKeyPress(sender, eventArgs) {
if (eventArgs.get_domEvent().keyCode == 13) {
sender.raise_Page_Load();
}
}
</
script>
This works, I can raise a page load here.
Lets have a look at the ComboBox.
in an example I found the following to get a Combobox behave like autosuggestion:
<telerik:RadComboBox ID="RadComboBox1" runat="server" Width="270px"
EnableLoadOnDemand="true" ShowToggleImage="false" LoadingMessage="..."
OnClientKeyPressing="onKeyPressing"
OnClientDropDownOpening="onDropDownOpening"
OnClientItemsRequesting="onItemsRequesting"
OnClientBlur="onBlur">
</telerik:RadComboBox>
and
<script type="text/javascript">
function onKeyPressing(sender, eventArgs) {
if (eventArgs.get_domEvent().keyCode == 13) {
sender.raise_Page_Load(); /* fails */
}
else {
sender.allowOpenDropDown = true;
}
}
function onDropDownOpening(sender, eventArgs) {
if (!sender.allowOpenDropDown || sender.get_text().length == 0)
eventArgs.set_cancel(true);
}
function onItemsRequesting(sender, eventArgs) {
if (sender.get_text().length == 0) {
if (sender.get_dropDownVisible())
sender.hideDropDown();
eventArgs.set_cancel(true);
}
}
function onBlur(sender) {
sender.allowOpenDropDown = false;
}
</script>
The problem:
sender.raise_Page_Load() fails when enter key is pressed.
Why is the behaviour not the same as with RadTextBox?
In my opinion there is only a client side sender.raise_Page_Load() for
the combobox missing, and we can implement a nice google-like autosuggestion
function!
Or, asked in another way:
How can I raise the page load event in the onkeypressing clientside method
of RadComboBox?
Thanks in advance
Peter
Rank 2
I didn't remember I had posted this here. I finally solved the problem with a little trick which is not very elegant but it worked for me.
First add a Script Manager to the page, then add a ClientTextChange event to the Rad Combo Box.
Codes:
JS:
function my_rcb_TextChange(sender, args) { var thekey; if (event.keyCode) { // tweak for cross-browsing thekey = event.keyCode; } else { // tweak for cross-browsing thekey = event.which; } if (thekey == 13) { __doPostBack('<%= my_rcb.UniqueID %>', 'enter_was_pressed'); }}And in the Page_Load event, in code-behind add some lines like this:
bool EnableEventoOnEnter = Request.Params["__EVENTARGUMENT"] == "enter_was_pressed" ? true : false; if (!this.Page.IsPostBack) { if (handler != null) { this.rcb_empleados.OnClientTextChange = "my_rcb_TextChange"; // Add OnClientTextChange event. Use this declaration if you want to control the event only if the handler is set. } } // if enter was pressed and the handler is not null, then execute the handler with the expected parameters if (EnableEventoOnEnter && (handler != null)) { handler(this.rcb_empleados, this.rcb_empleados.Text); }Any help you may need, just tell me :)
(note that I use this as a web-user-control, so that's why it may look weird the way I call everything)
Rank 1
I'm working also with RadComboBox in a Web-User-Control and with Scriptmanager
I will try your suggestions. Thank you very much.
Nevertheless, Telerik should provide the standard basic functionality for all their controls.
@Telerik:
do you have a nice example for a google like autosuggestion AND pageload on
enter key pressed on client side? This means a combination of
- the sender.raise_Page_Load() of RadTextBox
- and the dropdown on text enter of RadComboBox
- without tricks and with elegant code?
Regards
Peter
Rank 2
Let me see if I can explain my code:
The first code only filter pressed keys in order to catch a "return" key (code 13). I use .keyCode or .which because of browsers, for some browsers works one and for others work the another one. Finally, if return was pressed, I call a __doPostBack function, which forces a postback. In the server will execute the Page_Load event and in the EVENT_ARGUMENT and EVENT_TARGET you will receive the parameters you send in __doPostBack .Take a look at this: http://tipsdegabo.wordpress.com/2011/05/12/uso-de-__dopostback/ It explains the use of __doPostBack in spanish (you can use a google translator if you don't understand spanish (it's my personal blog ;) )
You can filter Request.Params["EVENT_TARGET"] and Request.Params["EVENT_ARGUMENT"] to seek for the parameters you send from javascript. That's what I do.
I use the "handler" because I created the event "OnEnter" in the user control. To see how to delegate events in web-user-controls, please refer to http://chiragrdarji.wordpress.com/2007/08/23/raise-event-from-user-control-to-main-page-event-delegation-from-user-control-to-aspx-page-in-aspnetc/
I hope I answer some of the questions you may be wondering.