I have a model "address", and one field is country, in the create/edit form I use dropdown to let user select from country list, country list is store in another model called "listCountry", there are 249 countries in total, but in the dropdown options, only first 100 countries shown.
My questions and concern are:
In the options setting, I use #datasources.listCountry.items..Country, and I know there is a default pagesize of 100, but I tried to change that property pageSize as suggested by google's doc, I added to Event Load of that dropdown app.datasources.listCountry.query.pageSize = 300;, but it doesn't work, any suggestion?
I tried Search Box instead of dropdown as workaround, it works, but it requires to set a relation between Address model and listCountry model, which is not required when I use Dropdown. I'm wondering which is the best practice to store an option list, like in this case when we need give an list options such as country for an address form, is that relation setting necessary?
Thanks in advance.
Related
In App Maker, what is the simplest way to achieve the same result with a dropdown box that you can with a suggest box, which can return the whole record when you make a selection giving you the ability to assign associated record values to other fields on the page?
Consider a data model with three fields, (Code, Description, and Severity). Add a dropdown box to select the Code. Have the selection, (probably using onValueChange or onValueEdit), write the selected Code's Description to a label field beside the dropdown box. The Code's Severity will also be used to affect the style in some way like background color or something, but for this answer, merely assigning the value to a scripting variable will be good enough. It's the record value access and assignment mechanism I am after.
Clarification: This data model will not be the page's datasource. It is a secondary reference table used for assigning a code to a ticket. You can also assume that a record value will be written to a field in the page's datasource as well.
I would appreciate the simplest low code solution as we will have non-programmers attempting this. Thanks.
As long as you leave your value binding on the dropdown blank the following should work:
Set the options binding to:
#datasources.YourDatasource.items
You may want to consider changing the 'Names' binding to be the projection of a particular field in this datasource otherwise the values showing in your dropdown will only be the 'keys' from this datasource.
Then in your onValueEdit event you will gain access to individual fields like this:
var item = widget.datasource.item;
item.YourFieldToEdit1 = newValue.YourOtherDatasourceField1;
item.YourFieldToEdit2 = newValue.YourOtherDatasourceField2;
That would probably be the simplest way.
I have two models, Country and City and a one-to-many relationship between them. One country can have many cities and a city can only have one country. App Maker generates a Country_fk field in the City model.
Now when I create a Create form and drop a form bound to the City model and include the related Country field App Maker creates a dropdown with the following:
options: #datasources.Country.items
value: #datasource.item.Country
Which, if I compare it with some example apps looks absolutely fine. However, I only get the Id of the related Country field not the country name field.
This has happened so many times with different models. I did once manage to create a relationship that worked, and it used the same datasource options and value values, but I can't for the life of me see why something so simple as this is so hard to do. it is so basic newbie stuff I'm beginning to give up on App maker.
You can use a little bit of help from the official documentation.
When you create a model, you can select the default display field. App Maker uses the default display field when it refers to a record in the model. A display field is commonly used for widgets that select a record, such as dropdowns.
Go to your model and make sure you select the proper display field. Something similar like in the image below.
You need to make the required field the 'Display Name' in the relevant model. Once you do this it will display as you want 👍
I am trying to implement a Many-to-Many relation between a class and its students in a form.
The form can be used to create or edit a class. Also students can be added to that class. To reduce the effort needed to enter students, I would like to add a multi-select that shows the entries from the students-table. But since the number of students is expected to be large, I would like to filter this multi-select.
I checked this question on filtering lists and the sample app "Project List. I understand that the standard workflow with a table would be to bind the value of a search box to the #datasources.STUDENTS.query.filters.email._contains and set the tables datasource property to STUDENTS
But, as I understand it, a multi-select element's value property must be bound to #datasource.item.students and its datasource property must be CLASS in order for the auto-saving to work.
Hence I wonder whether it is possible to filter a multi-select element.
I don't see the problem, but I think I see a misunderstanding.
You said: "I understand that the standard workflow with a table would be to bind the value of a search box to the #datasources.STUDENTS.query.filters.email._contains"
You need to bind the OPTIONS (not value) to the datasource query, as it is the options that will draw its records from the #datasources.Students.query datasource.
You can then set the VALUE of the multi-select widget to #datasource.item.students (where you want selected values from the student query options to be saved).
You will also need to set the NAMES property (since the options are likely student records). Names will be the Student datasource projection of whatever string field you want to appear in the options list.
I have an issue related to the data filtering. I have a Google Drive table to store data, and I want to show one field of this data source in a dropdown to make a filter by this field (Country).
The problem is that this dropdown filter it's only showing the countries that appears on the current page of the list. For example, if in the first page appears one country (Thailand) on the dropdown I'll only see Thailand.
If we move to the second page of the list we have another two countries (Spain and Portugal) and then the dropdown will only show Spain and Portugal.
What I really want is a dropdown which shows all the countries, no matter if they aren't on the current page, but I don't know how to fix it.
This the the configuration of the Country Selector:
In the help, it's said we should use #datasource.model.fields.COUNTRY.possibleValues,
but if I use this paramater as Options, nothing is displayed in the selector.
I have spend a lot of hours trying to fix this issue and I don't find the solution, and I would like to check with you if it's an issue or I'm doing something wrong...
Could you help me?
You are using the same datasource for your dropdown and table and by #distinct()#sort() you are filtering items that are already loaded to browser (opposed to the whole dataset stored in database).
You need to have a separate datasource for your dropdown. There are at least three techniques to do this:
Possible values
You can predefine allowed values for your Country field and use them to populate drop down options both in create form and table filtering #datasource.model.fields.Country.possibleValues as you mentioned in question:
Create model for countries
By introducing dedicated related model for countries you can get the following benefits:
normalized data (you will not store the same country multiple times)
you'll be able to keep your countries list clean (with current approach there is possibility to have the same country with different spellings like 'US', 'USA', 'United State', etc)
app users when they create new records will be able to choose the country they need from dropdown (opposed to error prone typing it every time for all new records).
your dropdown bindings will be as simple as these:
// for names
#datasources.Countries.items..Names
// for options
#datasources.Countries.items.._key
// for value
#datasource.query.filters.Country._key._equals
Create Calculated Model
With Calculated Model you'll be able to squeeze unique country values from your table. You server query script can look similar to this:
function getUniqueCountries_() {
var consumptions = app.models.Consumption.newQuery().run();
var countries = [];
consumptions.reduce(function (allCountries, consumption) {
if (!allCountries[consumption.Country]) {
var country = app.models.CountryCalc.newRecord();
country.Name = consumption.Country;
countries.push(country);
allCountries[consumption.Country] = true;
}
}, {});
return countries;
}
However with growth of your Consumption table it can give you significant performance overhead. In this case I would rather look into direction of Cloud SQL and Calculated SQL model.
Note:
I gave a pretty broad answer that also covers similar situations when number of field options can be unlimited (opposed to limited countries number).
I have a view with a filter by country. Country is an optional CCK text field with drop-down list selection from a predefined list.
When I expose the field as an optional view search filter, I can select a country on the filter form just fine, but how can I handle no selection? I want the user to be able to "un-select" any previously selected value so that the query runs for all countries (or, to be more precise, does not constrain the results by country). I cannot add "all" as a value to the CCK field for obvious reasons. Selecting all countries in the drop-down on the search filter is not very user-friendly and causes the page to time out (there are over 200 countries in the list, and I can only imagine the resulting SQL query). Whats the best way to handle this?
I found this View Filters Reset hack which could be helpful. The desire to memorize the last selection adds another complication - when configured in the View properties, and once the (persistent) cookie is set, there is no way to get rid of the selection (short of manually deleting the cookie).
The answer was to check "Force Single" on the filter properties. This made <any> show up as a selection in the country filter drop-down. It kind of makes sense, because <any> in a multiple-selection list could be seen as ambiguous. Still, I can think of valid reasons why a multiple selection filter might be optional. Drupal surprises me every day.