Updating ComboBoxItem optionDataSource

[danaconway]

I'm using SmartClient_v121p_2020-04-14_PowerEdition. I have a form with a ComboBoxItem defined, where the ComboBoxItem is backed by a client only DataSource. Upon load of the application, I query the DB and set the data in the DataSource. Example code below:

let comboDS = isc.DataSource.create({
   ID: "comboDS",
   field: [
      {name: "id", primaryKey: true},
      {name: "item_name"},
      {name: "category"}
   ],
   dataFormat: "json",
   clientOnly: true
});

let comboForm = isc.DynamicForm.create({
   ID: "comboForm",
   width: "100%",
   height: 30,
   fields: [
      {name: "selectItem", title: "Select item", defaultValue: defaultID, width: 200, editorType: "ComboBoxItem", completeOnTab: true, 
         addUnknownValues: false,  optionDataSource: comboDS, displayField: "item_name", valueField: "id", pickListWidth: 200, autoFetchData: true,
         changed: function(form, item, value) { // do something here }
      }
   ]
});

// Get data from DB
let comboData = getFromDB();
comboDS.setCacheData(comboData);

This works as designed. I have a use case where the user can add another "item" in another part of the application. When this item gets successfully saved to the DB, I do the following, so that the user has the option to select that item and view details of it at a later time:

let newItem = {id: newID, item_name: newItemName, category: "someCategory"};
comboDS.addData(newItem);

This too works great. Note that I am obfuscating what the application actually does per my company policy, so what come next may not make sense, but it's a valid use case in this application. The use case is that the system behind the application can get "reset". When this happens, I need to clear out all of the "items" from the drop down list. Once the reset is complete, I need to re-initialize from the DB, at which point all of the "new items" that were added would not be there, so would need to be removed from the ComboBox.

On reset, I tried to set the DataSource's cached data to an empty array to clear the ComboBox. This did not work. Also, when I tried to re-initialize from the DB (same as above), the list also did not update.

comboData.setCacheData([]);

I read a post from 2012 in the forum that basically said that "Select items do not fully support having their optionDataSource modified at runtime....". https://forums.smartclient.com/forum...election-issue

Is this still the case? Is there not a way to modify the optionDataSource at runtime?

Thank you.

[Isomorphic]

You can clear out the data in the DataSource with setCacheData(), but this not automatically cause a ComboBoxItem to re-fetch, just as it would not happen if the data were updated on the server side (what a clientOnly DataSource simulates). Use comboBoxItem.fetchData() to cause a new data fetch.