MVC Html.textbox/dropdown/whatever won't refresh on postback - asp.net-mvc-2

OK, let's start with the Html.Textbox. It is supposed to contain text read from a file. The file read is based on what the user picks from a dropdown list.
The first time it is fine. The user picks a value from the dropdown list. The controller uses that value to read some text from a file, and returns that text to the view via the view model. Everything is fine.
THen the user picks another value from the dropdown list. The controller reads a new value from a file and returns it via the view model. Debugging to the LINE BEFORE THE HTML.TEXTBOX is set in the view shows that the model contains the correct value. However, the textbox itself still shows the PREVIOUS value when the page displays!
If I switch from Html.Textbox to a plain input, type="text" html control, everything works fine. That's not so hard, but the same thing happens with my dropdown list -- I can't set the selected value in code. It always reverts to whatever was chosen last. Rendering a "select" tag with a dynamically-generated option list is a pain. I would love to be able to use Html.Dropdown.
What am I missing here?? This is such a simple thing in webforms!

When you post a form, the values that are posted are put into ModelState. When the HtmlHelper renders an html iunput element, e.g. Html.TextBoxFor(x => x.FirstName), it'll search various locations to get the value for the textbox... ModelState is before ViewData.Model in the list of locations. So there for, the previously posted value will appear in your textbox.
To fix this you could clear the ModelState value or update the ModelState value. BUT I would kinda view that as a hacky way of getting around the problem.
The real issue has more to do with the flow of the posts and requests. I would personally look into that and maybe implement the PRG (Post Redirect Get) pattern.
HTHs,
Charles

Following on from what Charles/Charlino said:
Model binding updates the ModelState object, which contains validation and model binding errors that are collected during model binding.
Inside an action method, model binding has occurred already to update the model, and generated the ModelState object. If you now update the value on the model inside the action, you must also manually update the model state (since the helpers use it to generate their HTML). Below is an example:
model.CaptchaIsValid = CaptchaService.ValidateAndExpireCaptcha(model.CaptchaAttempt);
if (!model.CaptchaIsValid)
{
ModelState.AddModelError("CaptchaAttempt", "Incorrect - please try again");
}
// I'll clear the value on each attempt, to force them to re-enter a CAPTCHA.
model.CaptchaAttempt = string.Empty;
// Since I updated the model, I must create a new ValueProvider result...
ValueProviderResult clearedValue = new ValueProviderResult(
model.CaptchaAttempt,
model.CaptchaAttempt,
CultureInfo.CurrentCulture);
// ... and update the ModelState's value.
ModelState.SetModelValue("CaptchaAttempt", clearedValue);

The biggest issue I see here is that you are trying to do a postback within MVC. That model is really not supported, and is actually way more trouble than it is worth (as it seems you are finding out). I would recommend using Ajax to update the contents of the dropdown dynamically.

Related

Lightswitch HTML Client, Set Default Value of List Picker

Lightswitch renders my navigation property as a list picker, but I can't figure out how to set a default value on it. There must be a simple way to do it. I've scoured the net, and all the suggestions look hopelessly kludgy. Is there a good comprehensive tutorial out there for Lightswitch? The most common tasks like setting the default value on a dropdown are ridiculously hard to figure out.
Here's how I did it.
myapp.Address.created = function (entity) {
myapp.activeDataWorkspace.MailListData.CountryRegion_LUs.filter("CountryRegionCode eq 'US'").execute().then(function (result) {
entity.CountryRegion_LU = result.results[0];
});
}
You want to write a handler for the created Javascript event for the parent entity. I'm binding CountryRegion_LUs, which are in the Address entity, so I am binding to the created event of the Address entity, not the CountryRegion_LUs entity. "MailListData" is the name of my database. I'm using an OData query to pull out the CountryRegion_LU that has a CountryRegionCode of "US." I could have simply used "load()" instead of .filter("CountryRegionCode eq 'US'").execute() to load all the records, and then picked the member of the result-set I wanted, say results.result[221], but then I'd be bringing all the data over and filtering client-side.
refer to this post of which I asked myself, there is a detailed answer on the problem you have above: it explains how to set your modal picker/details picker with a default value
Lightswitch HTML Client - set modal picker value when screen created
any questions feel free to ask

Live search combo in Ext JS 4.2.2

I'm trying to implement a live search combo. It suppose to work like this:
When I enter a character into the combo field I read the current value and send it as a parameter to the store's url. In the backend the parameter is used to return any value from the database that contains it, so the store behind the combo gets filled only with those filtered values.
As I continue to enter characters into the combo, the parameter should be updated and sent again to the backend and so on, getting like this a smaller and smaller store.
I tryied to achieve this behaviour using the combo's event keypress, even keyup, but the problem is it's impossible for me to get access to the current value from the combo field.
For example, when I entered the "for" string into the combo, how can I obtain this value using the combo object? comboName.getValue() doesn't work, it returns nothing "".
I already saw the live combo example here: http://docs.sencha.com/extjs/4.2.2/#!/example/form/forum-search.html but doesnt help me at all.
So my big question is: how do i get the current value while still editing the combo's field?
Any help would be appreciated, thanks.
You should be able to use
comboName.getValue();
or
comboName.getRawValue();
Where comboName is your combo box. Are neither working- I note in your post you state getValues() which is an improper method. You may want to also check whether when you're referring to your combo box object, that the reference is actually correct. The first argument from the key events is actually the object itself, so you should be able to do, e.g.
listeners:{
keyup:function(comboBox){
var value = comboBox.getValue() || comboBox.getRawValue();
console.log(value);
}
}
Swapping you the value getting method as appropriate.
I found that the combo already has a quick search behaviour, I just have to set queryMode on 'remote' and some other small configurations. More details here:
Ext Js 4.2.2 combobox queryMode

Symfony2: Entity instantiation upon Form-Submit depending on user selection

I'm working with Symfony2 to set up a form, where a Shelf-Entity can be edited.
A shelf contains a collection of Readable-Entities (e.g. Book, Magazine, etc. - all inherit from Readable).
The user has the possibility to add more Readable-Entities (the form is extended via JavaScript) and from a dropdown he can select the type of Readable he wants to add. Depending on the selected dropdown-value, different form fields are rendered. So far so good.
Now, when the form is submitted to the server, depending on the Readable-Type the user selected in the form, a different entity-type should be instantiated.
If I don't do anything, Symfony just instantiates the base class Readable (and not Book, Magazine, etc.).
How can I tell Symfony to instantiate the correct type of Readable depending on the selected value from the dropdown?
I tried with FormEvent-Listeners, but:
in PRE_SUBMIT I only get an array containing the "raw" form data with $event->getData(), i.e. no entities have been instatiated so far. However, at this stage, I still have access to value of the dropdown.
in SUBMIT the form data was already assigned to the appropriate entities. Also the new Readable was already instatiated with the base Readable-Class. But now, I cannot access anymore the value from the dropdown.
What is the correct way to do this?
EDIT
Added a minimal Code-Example for the Shelf FormType:
https://gist.github.com/anonymous/401495b701982adafb96
Code for infinite_form_polycollection:
https://gist.github.com/anonymous/b5f0ed10ca9c52177f01
Have you tried looking at this part of the doc? As "embedding a form" seems to fit your needs.
It seems that there was something wrong with the PHP-Files of the PolyCollection in the vendor-directory, because after removing everything related to the Infinite Form Bundle from the vendor-dir and reinstalling it with composer, everything is working now. But thanks for your efforts YoannCh

ExtJS 4 - How to load grid store with its params carrying latest values from a form?

I have a window with a search form at the top and grid at the bottom.
User can enter values in the search form and click button - Get Records.
At the click of this button, I load the store of the grid by passing the values in form fields as parameters in following way:
store.load({
params:{
key1:Ext.getCmp('field1').getValue();
}
});
I tried giving parameters in the store proxy itself, but it unfortunately always takes up initial values (values when the form is rendered) and not the latest one entered by the users in the form fields. Following is the method I used for assigning values to params while creating the store:
extraParams:{
key1:Ext.getCmp('field1').getValue();
}
I wanted to seek guidance at two things:
a. While defining a store, can I ensure that store takes latest/current values from the form fields before querying server, so that I don't have to provide these values while calling load function?
This becomes more necessary as I have a paging toolbar at the bottom which carries a refresh button (along with next, last, previous, first icons for navigation).
Now, whenever user clicks at refresh (or any navigation icon), the store gets loaded without the query parameters.
Thus the second thing is:
b. If the answer of 'a' is that - Pass the latest values to parameters manually when calling load function - then how can I write the handler for 'refresh' button and navigation icons (that is, next, last, previous and first) in the paging toolbar, so that I can pass the latest form values to load function.
Thanks for any help in advance.
PS: I am using ExtJS 4.
yourStore.on('beforeload',function(store, operation,eOpts){
operation.params={
status:cmbStatus.getValue(),
value:txtBuscarPor.getValue(),
empresa:'saasd',
app:'dsads'
};
},this);
Related to your question (b) (and because you especially asked for this in the comments section):
I see only one standard way to hook into the PagingToolbar button handlers which is very limited.
Ext.toolbar.Paging fires a 'beforechange' event before it actually changes the current page. See API docs. A listener that returns false will stop the page change.
All other methods require extending Ext classes which wouldn't be a problem if the ComboBox would make it easier to use your own implementation of BoundList (which is the class that renders the dropdown) or pass through config parameters to BoundList resp. the paging toolbar.
I tried to bring this lack of flexibility up on the Ext message board once but was pretty much ignored.
A possible solution for this is to use 'beforeload' event of the store and provide the list of parameters in it. This way, whenever the store is loaded, then its beforeload event is fired and the values picked up are always the latest. Hope this helps someone looking for something similar.

Showing an initially selected object in an ObjectAutoCompleteField on page load in Wicket

I've followed the Wicket by Example guide to get the ObjectAutoCompleteField working, and it does so quite nicely.
I have a huge problem, though, and that is to show an initially set object in the field when the page loads. The object is retrieved from a model I use for the form where the ObjectAutoCompleteField is used. Changing the ObjectAutoCompleteField changes the model attribute it is "connected" to, and any subsequent changes in the field shows the appropriate label in its place, just not the initial one when the page loads—the only thing that shows is the edit link (to get to the autocomplete functionality).
I've looked around in the documentation for the ObjectAutoCompleteBuilder but haven't found any corresponding method to even set the initial value explicitly on page load.
I finally managed to find a solution by looking through the classes relating to ObjectAutoCompleteField.
The ObjectAutoCompleteField is constructed by the build method in ObjectAutoCompleteBuilder. So, by calling the readOnlyRenderer method on the builder, creating a new ObjectReadOnlyRenderer creating a label inside its getObjectRenderer, I got the ObjectAutoCompleteField to render a preselected object on page load.
ObjectAutoCompleteBuilder<Author, Long> builder = new ObjectAutoCompleteBuilder<Author, Long>(provider);
builder.readOnlyRenderer(new ObjectReadOnlyRenderer<Long>() {
public Component getObjectRenderer(String id, IModel<Long> pModel, IModel<String> pSearchTextModel) {
return new Label(id, new PropertyModel<Author>(model, "author"));
}
});
One would think that this was the standard behaviour, but now I know for future reference.