Updating Django form based on input - ajax

I want to append more fields based on a users selection of Type of Event.
What is the best way to add additional fields based on the users selection without refreshing the page?
I was thinking ajax call when user clicks Add the details and return html?
Is there a way to do this using the template system with a series of if/else conditionals?

Two solutions come to mind here...
1)
Attach a jQuery change handler to the 'Type of Event' select element, and execute an ajax request to return the dynamic fields that will need to be displayed.
$('#TYPE_OF_EVENT_ID').change(function() {
$.get('/api/to/return/dynamic/fields/', {'type_of_event': $(this).val()}, function(data, textStatus, jqXHR) {
# Update DOM with dynamic content return by data (should probably be JSON)
});
});
2)
Hard code the logic straight into your javascript to handle the case statements to display the dynamic fields depending upon the value which is selected in the 'Type of Event' select element.
$('#TYPE_OF_EVENT_ID').change(function() {
switch($(this).val()) {
case 'Special Event':
# Show Special Event Fields
case 'Non Special Event':
# Show Non Special Event Fields
}
});
I'd recommend option 1 as it scales better keeping this logic on the server to be database driven.

Related

Fullcalendar Problems w/ filtering Events in agendaDay-View (works only one time, then no more events exist)

I have a problem with filtering events:
I use fullcalender in agendaDay-View
I use a drop-Down list to select a driver
I compare the name (it is a property of event-object) with the selected value
(this part is ok)
Then,
I remove all Events (.fullCalendar('removeEvents');)
Add the specific events
(add with renderEvents doesn't work proberly at the moment)
And now my problem appears:
For the first time it works, however, when I select another 'driver', the events are gone, because of the 'removeEvents'-Action before.
So, how can I solve this problem, that I can only display the filtered events and keep the other (actualley all events) to filter again for second, third n- time?
$('#' + id).fullCalendar('refetchEvents');
was the first idea, however, its brings all back and selected Issues were doubled (and so on).
I'm thankful for every hint.
Ok I think you can solve your problem with fullCalendar's eventRender function.
The function can also return false to completely cancel the rendering of the event.
Your event from events.json should have a property like 'driver_id'.
I would have select field instead of dropdown with option keys being driver ids, values - names or whatever. Lets say it's id would be 'driver_select'.
Then render events like this:
$('#calendar').fullCalendar({
//...
eventRender: function(event, element) {
//driver select should have default value assigned or else no events will be rendered
if ($("#driver_select").val() !== event.driver_id) {
return false; //do not render other driver events
}
}
//...
});
Handle select changes to update
$("#driver_select").off('change').on('change', function() {
$("#calendar").fullCalendar( 'refetchEvents' );
});
Another approach would be to show all drivers in a timeline. For that you can use FullCalendar Scheduler.

How to trigger DataBinding Validation for all Controls?

I have an OpenUI5 form consisting of a number of Inputcontrols. These Inputcontrols are bound to a model using the OpenUI5 DataBinding as described in the documentation.
For example:
new sap.m.Input({
value: {
path: "/Position/Bezeichnung",
type: new sap.ui.model.type.String(null, {
minLength: 1,
maxLength: 128
})
}
})
As in the example above I'm using constraints on the stringlength.
When a User changes the Value of the Input, the Validation is triggered and according to the Validationresult one of the functions descripted here is called.
In these functions I'm setting the ValueState of the control like this:
setupValidation: function() {
var oCore = sap.ui.getCore();
oCore.attachValidationError(function (oEvent) {
oEvent.getParameter("element").setValueState(sap.ui.core.ValueState.Error);
});
oCore.attachValidationSuccess(function (oEvent) {
oEvent.getParameter("element").setValueState(sap.ui.core.ValueState.None);
});
oCore.attachFormatError(function (oEvent) {
oEvent.getParameter("element").setValueState(sap.ui.core.ValueState.Error);
});
oCore.attachParseError(function (oEvent) {
oEvent.getParameter("element").setValueState(sap.ui.core.ValueState.Error);
});
},
Let's assume the bound model variable is initial.
I'm loading the view, the property value is parsed and displayed as empty.
The Validationerror/Parseerror method is not called although the constraints are not met.
This seems to be standard behaviour of OpenUI5. Only changes in the Control will be a validated.
Now let's assume I've a submit button and the Value of the Inputcontrol is still empty. When the user hits the submit button I'd like to trigger the DataBinding Validation for all childcontrols of my view. This would validate the above mentioned input and would result in an errorstate.
My question is: How can I trigger the databinding validation for all childcontrols of my view?
There is another question on SO where the poster asks for a way to define required fields. The proposed solution is to call getValue() on the control and validate the value manually. I think this is kind of cumbersome as formating and constraint information and logic is already present.
I suggest looking into field groups.
An example here in the UI5 docs
Field Groups allow you to assign group IDs to the input fields. Then you can call all of the input fields at once. You can set the name property and required property on each <Input> separately in your view, allowing you to handle some logic when you perform validation.
You can call this.getView().getControlsByFieldGroupId("fieldGroupId"), which will return an array of the input controls. Then you can loop through the controls, pass them through your logic, and use setValueState() to show the results.
Or, you can assign the validateFieldGroup event on the parent container, which is usually a form, but can be anything like a <VBox> that contains the controls. When the users focus moves out of the field group, the event is fired. You can then use the event handler in your controller to perform the validation.
In your case, I would assign a press event to your submit button, and in the handler, call the field group by ID and loop through the controls. At the end of your function, check to see if all fields are validated before continuing.
View
<Input name="email" required="true" value="{/user/email}" fieldGroupIds="fgUser"/>
<Input name="firstName" required="false" value="{/user/firstName"} fieldGroupIds="fgUser"/>
<Button text="Submit" press="onSubmit"/>
Controller
onSubmit: function() {
var aControls = this.getView().getControlsByFieldGroupId("fgUser");
aControls.forEach(function(oControl) {
if (oControl.getRequired()) {
//do validation
oControl.setValueState("Error");
oControl.setValueStateText("Required Field");
}
if (oControl.getName() === "firstName") {
//do validation
oControl.setValueState("Success");
}
});
var bValidated = aControls.every(function(oControl) {
return oControl.getValueState() === "Success";
});
if (bValidated) {
//do submit
}
}
The concept goes like this.
Use custom types while binding, to define validations. Validation
rules go inside these custom types (in the method 'validateValue').
When Submit is pressed, loop through the control hierarchy and
validate each control in your view. (By calling 'validateValue'
method of the Custom Type).
Validator (https://github.com/qualiture/ui5-validator ) uses this concept and it is a small library to make your life easy. Its main advantage is that it recursively traverses through the control library.
Using Message Manager (using sap.ui.get.core().getMessageManager() ) is the way to show the validation messages on the UI control.
Triggering data binding validations is not possible. Rather for empty fields that are having required property true you can do a work around using jQuery.
Please refer my answer to this same problem at Checking required fields

implement chanied filters/seach options in a datagrid using ajax

Let´s say I have some sort of datagrid and I want to add a couple chained filters like in this site:
http://www.yelp.com/search?find_desc=bar&ns=1&find_loc=Minneapolis%2C+MN
(sort by,distance,price etc).
Each time a user clciked in a filter link it will update the content of datagrid accordingly. But I would also need to update the links in other filters to take account of the changes. Ex: if i change the order field I need to add/update ?order_field=x in all the other filters links.
What you think is the best way to implement such scenario?
Should i create a function that, when a filter link is clicked, it update the query string params of all the other filters? Or use hidden fields to record the selected option in each filter?
I would like a reusable solution if possible.
Since the data is loading via AJAX, there shouldn't be any links to update - at least not if you mean anchor tags <a>. You don't even need to store the filters in a hidden field.
I would store all the filters as a JSON object. Depending on how your API is set up, you may have to convert the JSON object to something usable by your API or you may even be able to pass on the JSON object directly in the $.ajax request.
This sample code assumes you have a textbox with id="price" in the markup. I intentionally left convert_filters_to_parameters blank because you didnt provide any details as to your API. jQuery will in turn serialize those parameters into a GET or POST request before it sends them out.
var filters = {
distance:null,
price:null,
sortBy:'distance'
}
//this assumes you have a textbox with id="price"
$('#price').changed(function()
{
filters.price = $(this).val();
refresh_data();
});
function refresh_data()
{
var parameters = convert_filters_to_parameters(filters);
$.ajax('/my_api',
{
//i left out a lot of properties here for brevity
data: parameters,
success: function(response) { alert(response); }
});
}

Browser Memory Usage Comparison: inline onClick vs. using JQuery .bind()

I have ~400 elements on a page that have click events tied to them (4 different types of buttons with 100 instances of each, each type's click events performing the same function but with different parameters).
I need to minimize any impacts on performance that this may have. What kind of performance hit am I taking (memory etc) by binding click events to each of these individually (using JQuery's bind())? Would it be more efficient to have an inline onclick calling the function on each button instead?
Edit for clarification :):
I actually have a table (generated using JQGrid) and each row has data columns followed by 4 icon 'button' columns- delete & three other business functions that make AJAX calls back to the server:
|id|description|__more data_|_X__|_+__|____|____|
-------------------------------------------------
| 1|___data____|____data____|icon|icon|icon|icon|
| 2|___data____|____data____|icon|icon|icon|icon|
| 3|___data____|____data____|icon|icon|icon|icon|
| 4|___data____|____data____|icon|icon|icon|icon|
I am using JQGrid's custom formatter (http://www.trirand.com/jqgridwsiki/doku.php?id=wiki:custom_formatter) to build the icon 'buttons' in each row (I cannot retrieve button HTML from server).
It is here in my custom formatter function that I can easily just build the icon HTML and code in an inline onclick calling the appropriate functions with the appropriate parameters (data from other columns in that row). I use the data in the row columns as parameters for my functions.
function removeFormatter(cellvalue, options, rowObject) {
return "<img src='img/favoritesAdd.gif' onclick='remove(\"" + options.rowId + "\")' title='Remove' style='cursor:pointer' />";
}
So, I can think of two options:
1) inline onclick as I explained above
--or--
2) delegate() (as mentioned in below answers (thank you so much!))
Build the icon image (each icon type has its own class name) using the custom formatter.Set the icon's data() to its parameters in the afterInsertRow JQGrid event. Apply the delegate() handler to buttons of specific classes (as #KenRedler said below)
> $('#container').delegate('.your_buttons','click',function(e){
> e.preventDefault();
> var your_param = $(this).data('something'); // store your params in data, perhaps
> do_something_with( your_param );
> }); //(code snippet via #KenRedler)
I'm not sure how browser-intensive option #2 is I guess...but I do like keeping the Javascript away from my DOM elements :)
Because you need not only a general solution with some container objects, but the solution for jqGrid I can suggest you one more way.
The problem is that jqGrid make already some onClick bindings. So you will not spend more resources if you just use existing in jqGrid event handler. Two event handler can be useful for you: onCellSelect and beforeSelectRow. To have mostly close behavior to what you currently have I suggest you to use beforeSelectRow event. It's advantage is that if the user will click on one from your custom buttons the row selection can stay unchanged. With the onCellSelect the row will be first selected and then the onCellSelect event handler called.
You can define the columns with buttons like following
{ name: 'add', width: 18, sortable: false, search: false,
formatter:function(){
return "<span class='ui-icon ui-icon-plus'></span>"
}}
In the code above I do use custom formatter of jqGrid, but without any event binding. The code of
beforeSelectRow: function (rowid, e) {
var iCol = $.jgrid.getCellIndex(e.target);
if (iCol >= firstButtonColumnIndex) {
alert("rowid="+rowid+"\nButton name: "+buttonNames[iCol]);
}
// prevent row selection if one click on the button
return (iCol >= firstButtonColumnIndex)? false: true;
}
where firstButtonColumnIndex = 8 and buttonNames = {8:'Add',9:'Edit',10:'Remove',11:'Details'}. In your code you can replace the alert to the corresponding function call.
If you want select the row always on the button click you can simplify the code till the following
onCellSelect: function (rowid,iCol/*,cellcontent,e*/) {
if (iCol >= firstButtonColumnIndex) {
alert("rowid="+rowid+"\nButton name: "+buttonNames[iCol]);
}
}
In the way you use one existing click event handler bound to the whole table (see the source code) and just say jqGrid which handle you want to use.
I recommend you additionally always use gridview:true which speed up the building of jqGrid, but which can not be used if you use afterInsertRow function which you considered to use as an option.
You can see the demo here.
UPDATED: One more option which you have is to use formatter:'actions' see the demo prepared for the answer. If you look at the code of the 'actions' formatter is work mostly like your current code if you look at it from the event binding side.
UPDATED 2: The updated version of the code you can see here.
You should use the .delegate() method to bind a single click handler for all elements ,through jQuery, to a parent element of all buttons.
For the different parameters you could use data- attributes to each element, and retrieve them with the .data() method.
Have you considered using delegate()? You'd have one handler on a container element rather than hundreds. Something like this:
$('#container').delegate('.your_buttons','click',function(e){
e.preventDefault();
var your_param = $(this).data('something'); // store your params in data, perhaps
do_something_with( your_param );
});
Assuming a general layout like this:
<div id="container">
<!--- stuff here --->
<a class="your_buttons" href="#" data-something="foo">Alpha</a>
<a class="your_buttons" href="#" data-something="bar">Beta</a>
<a class="your_buttons" href="#" data-something="baz">Gamma</a>
<a class="something-else" href="#" data-something="baz">Omega</a>
<!--- hundreds more --->
</div>

JQuery - which form was submitted?

I have a page of products and for each of them, I want to have a form that uses AJAX to update the session. I've done this bit - just providing background.
I use the product's ID to create a different form class and name for each form, so each form is called something like this_form_name_567 and the next would be this_form_name_568 and so on.
There is a submit button per form. I'm having trouble figuring out
Which event is best to use so that the correct form will be identified when a submit button is clicked?
Once clicked, how to then make sure the correct value is taken from a hidden field (unique ID) within the submitted form so that I can populate a line of code such as:
$.post("compare_response.php", {compare_this: $("#compare_this").val()}, function(data){
}
You can use the .closest tree traversal method to get the form in which the button of interest is nested:
$("input[type=submit]").click(function() {
alert($(this).closest("form").attr("id"));
});
or even simpler, just get the element's form property :)
$("input[type=submit]").click(function() {
alert(this.form.id);
});
You can try it out here.
You can get the form you are submitting like this:
$('form').submit(function() {
var yourForm = $(this);
var hiddenValue = $(this).find('input[type=hidden]').val();
});
Of course you can get the hidden value differently, or if you have more than one hidden you'll have to give a little more information about it.

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