I am using Vaadin 8 NativeSelect as a dropdown for users to make selections. Each selection refers to an object instance that holds multiple pieces of data and I only want the dropdown to display one piece of identifying information pertaining to a single variable in that object however it doesn't seem like NativeSelect can handle Model and Presentation separately in an obvious way.
data class Consultant(
val name: String,
val id: Long
)
val consultantSelection = NativeSelect<Consultant>().apply {
setItems(consultantDao.getAll())
caption = "Select Consultant"
}
In my code, I create a NativeSelect handling a type of Consultant which then creates a dropdown menu that simply unpacks the contents of the respective Consultant objects as each selectable. I would like to only display the name of the Consultant in the selection.
Is there a way to achieve this?
You have to provide a setItemCaptionGenerator for this. Otherwise Vaadin falls back to the .toString() implementation.
There is a whole section about dealing with things around that in Vaadin Documentation
Related
I am trying to limit entities that the user can select from on "Regarding" field on Appointment form and set some default views used by these lookup fields.
The big idea is that when user is entering data in the field itself, the results should be provided from default view for this lookup, e.g. "Contacts I follow", but when user enters "Lookup more records" pop-up the default view should be swapped to "All contacts".
This field can look up in many entities, e.g. Account, Contact, Billing, etc., and I want to limit it strictly to Accounts only.
So far I've found two ways of doing it:
1) Add filters to lookup fields, so that any records not fulfilling given criteria will not be shown. This is done using addPreSearch JS function from Xrm lib, like this:
var addEventHandler = function (defaultView) {
Xrm.Page.getControl("contactid").addPreSearch(function () {
addFilter("contactid", defaultView)
});
}
var addFilter = function (entityName, defaultView) {
var filterXml = "<filter type = 'and'>" +
"<condition attribute='contactid' operator='null'/>" +
"</filter>";
Xrm.Page.getControl("contactid").addCustomFilter(filterXml, "contact");
Xrm.Page.getControl("contactid").setDefaultView(defaultView);
}
(This is just sample code, not actually applied to the Regarding field)
2) Second option is to use undocumented solution by using setLookupTypes function on the field itself, like this:
var limitLookupEntities = function () {
Xrm.Page.getAttribute("contactid").setLookupTypes(["contact"]);
}
var changeDefaultViewForLookup = function(viewGuid){
Xrm.Page.getControl("contactid").setDefaultView(viewGuid);
}
The issue:
The problem is that as mentioned earlier, "Regarding" field can look up in many entities. Limiting them using the solution 1) is tedious, having to create as many filters as there are entities and applying them one by one to the field doesn't seem the right way to go. However, the way I implement this, the default view behaviour works as intended - the look-in value is only changed for the pop-up window.
Solution 2) is way easier to implement, and won't require any changes in the future if any new entities would be added to relationship with "Regarding" field, but the default view is applied to both "in-field" and "pop-up" default view.
The solution I'm looking for needs to do the following:
It should limit the search to specified entity only
It shouldn't require any maintaining after being implemented, e.g.
in case new entities are introduced to "Regarding" field.
It should be generic - I might want to be able to parametrize it and use it on other forms
It should apply the default view change only when user opens the pop-up search window
Is it even possible?
The CRM version I'm implementing this on is 8.2 on-prem.
There is something I don't understand how to do with Gtkmm 3.
I have a custom business type that I have declared like this:
enum class Eurocents : int {};
I would like to render this type into a Gtk::TreeView which has a Gtk::ListStore as model. So I declare a Gtk::TreeModelColumn<Eurocents>, and add it to the model. I then append_column this model column to the Gtk::TreeView with an appropriate title.
I then append_row to the model and set the value corresponding to the column to (Eurocents)100.
The result I get is that the cell is displayed empty. Understandably so, because I would not expect Gtkmm to know how to render my arbitrary type.
I would like to instruct Gtkmm on how to render my type.
I already know how to display Glib types like Glib::ustring and formatting to Glib::ustring for display is possible, but it is not the subject of the question.
Is it possible to code columns that can display arbitrary types like this? And if so, how? What is required for sorting to work?
The most common, and easiest way, is to use a cell_data_func callback. For instance, you can create your own instance of a Gtk::TreeView::Column (the view column), pack a cell renderer (or more) into your Gtk::TreeView::Column, append your Gtk::TreeView::Column to the TreeView with Gtk::TreeView::append_column(), and call set_cell_data_func() on your Gtk::TreeView::Column():
https://developer.gnome.org/gtkmm/stable/classGtk_1_1TreeViewColumn.html#a3469e1adf42e5932ea123ec33e4ce4e1
You callback would then get the value(s) from the model and set the appropriate values of the properties of the renderer(s).
Here is an example that shows the use of set_cell_data_func(), as well as showing other stuff:
https://developer.gnome.org/gtkmm-tutorial/stable/sec-treeview-examples.html.en#sec-editable-cells-example
This link should also be useful:
https://developer.gnome.org/gtkmm-tutorial/stable/sec-treeview.html.en#treeview-cellrenderer-details
If you like, Gtk::TreeView::insert_column_with_data_func() makes this a little more concise: https://developer.gnome.org/gtkmm/stable/classGtk_1_1TreeView.html#a595dcc0b503a7c1004c296b82c51ac54
As for the sorting, you should be able to just call set_sort_func() to specify how the column is sorted: https://developer.gnome.org/gtkmm/stable/classGtk_1_1TreeSortable.html#a3a6454bd0a285324c71edb73e403cb1c
Then this regular sorting advice should apply: https://developer.gnome.org/gtkmm-tutorial/stable/sec-treeview-sort.html.en
I am having an odd problem with data loading which I don't understand, and I am hoping someone can explain to me what is going on, and perhaps how to accomplish my task more directly.
I am building a website using the technologies listed in the subject of this question.
I have a set of objects - each object has several properties (Name, ID, etc.) and a collection (ICollection<>) of other objects. So just looking at the tree of objects and their collections, it looks like this:
Tab
-TabRows
--Sections
---SectionRow
----Article
(So each tab has one or more tabrows, each tabrow has one or more sections, and so on. Each sub-object has a link back the parent, so each sectionrow has a SectionID, each Section has a TabRowID, etc.)
OK, so given that structure, consider this code:
// GET api/Tab/5
public Tab GetTab(int id)
{
var tab = db.Tabs.FirstOrDefault(t => t.TabId == id);
var tabrows = db.TabRows.ToList();
var sections = db.Sections.ToList(); // This makes the tabRow.Sections populate
var sectionrows = db.SectionRows.ToList();
var articles = db.Articles.ToList();
return tab;
}
So here is what happens. When the first line (var tab =...) executes, I get a tab object, but the TabRows collection is empty. (It is not null because the constructor instantiates it).
When the second line (var tabrows =...) executes, tab.TabRows suddenly populates. tab.TabRows.Sections is empty.
When the third line executes, tab.TabRows.Sections suddenly populates.
And so on.
I am assuming this is some sort of "lazy loading" on behalf of Linq, or perhaps one of the other technologies. But I don't know them well enough to figure it out.
Is there a way to re-write this so that I can just call line 1 and basically have everything auto-populate without having to individually reference every single object in every single collection?
Lazy loading is enabled by default and eager loading disabled. Entity framework allows you to hint at eager loading using the include statements. Your statement will become something like this.
var tab = db.Tabs.FirstOrDefault(t => t.TabId == id).Include("TabRows");
or as Include(t => t.TabRows);
Take a look at this link for more information.
In your case you would need to handle nested includes as well. Which means you would be better off taking another Model (your class) structured as follows
Tabs -> Containing a List<TabRows> -> containing a List<Sections> etc.
You would then need to re-write the linq so it populates the entire Model including the nested entities using nested includes.
As a side note, too many of these inner joins might slow down your querying and so consider indexed views on your DB side if and when possible
I am quite new to Qt and am in a situation where I want to use a model for my needs:
I have a dynamic number of instances of a subclass that need to be handled differently (different UI controls for each if it is selected). I want to get a list view where I can add new elements or delete old ones, as well as disabling/enabling existing ones.
Of course I want to rewrite as least of the code as possible, so I thought of utilizing the Listwidget and a ListModel to give some controls to the user. But how to link these (or better the items) to instances of the classes?
Do you know any tutorials on this?
I already looked in QtDemo and Google but I do not know the right words to search for
so I had no good results.
Basically what I think I need is a model item that accepts Collider* for its data.
But when I plug this into QStandardItem.setData() it says error: ‘QVariant::QVariant(void*)’ is private
So I found the solution to this problem.
As QStandardItems are capable of storing QVariants as data I wanted to store a pointer to my data in a QVariant. To achieve this I had to use Q_DECLARE_METATYPE(MyType*).
With this I was able to
MyType *MyInstance = new MyType;
QVariant data;
data.setValue(MyInstance);
QStandardItem *item = new QStandardItem("My Item");
item->setData(data);
standardModel->appendRow(item);
And the best is you can add as many types you want and let QVariant do the work to decide if it contains the type you wanted:
if(v.canConvert<MyType*>())
//Yes it is MyType
else if( v.canConvert<MyOtherType*>())
//Oh it is the other one
So finally this only requires to declare the meta type so you do not have to subclass any items.
Also you should read on the limitations of this here:
Q_DECLARE_METATYPE
qRegisterMetaType
Does this page answer your questions? There's an example of deriving a StringListModel item that you might be able to use as a template
Currently I'm developing a debate module (much like a scrum/kanban board) for a GPL application (e-cidadania) and I don't have any experience with complex backends. I have developed a basic frontend for it, but now I don't know what approach I should use for the ajax and django backends to save and manipulate the table and notes.
The table can be N rows and N columns, every row and column has a name and position inside the table. Every note has also a position, text and comments (managed with the django comments framework).
I thought to store the parent element of every note (so I can place it later) and store the name of the rows and columns like CSV strings. Is that a good approach?
A screenshot of the current frontend: http: //ur1. ca/4zn4h
Update: I almost forgot, the frontend has been done with jQuery Sortables (so the user can move the note around as he likes) and CSS3.
You just need to model your domain (that is, debates that look like scrum boards) within Django. Think about it in plain English first, like this:
The has debates. These consist of criteria, organised in rows and columns in a specific order. This creates cells, which can have notes inside them.
Then you can set to work translating this into model classes. Don't worry too much about the fields they contain, the most important bit is the relationships (so the ForeignKey bits):
class Debate(models.Model):
title = ...
class Column(models.Model):
title = ...
order = ...
board = models.ForeignKey(ScrumBoard, related_name='columns')
class Row(models.Model):
title = ...
order = ...
board = models.ForeignKey(ScrumBoard, related_name='rows')
class Cell(models.Model):
column = models.ForeignKey(Column)
row = models.ForeignKey(Row)
class Note(models.Model)
text = ...
cell = models.ForeignKey(Cell)
That might be overly complex for what you need, though. I'm not an expert in the problem you're trying to solve? My suggestion, Django is quick – so start hacking, and give it a go, and if it's all wrong then you can go back a few steps, clean out your database and try again.
You might find it useful to play with South, which does database migrations for when you do things like add/remove/edit fields in your models.