combobox - UI5: Why is the formatter called a second time with a 'null' value?

Question

I'm using a XML-Fragment defining a ComboBox where I want to add some core:CustomData with a value returned by a formatter. The formatter is called the first time when the fragment shows up and a second time when I open the dropdown list of the combobox. First time I get a single entry(from entries) from the model as expected. At the second call the parameter is null.

What am I doing wrong?

'myModel' is a static json model loaded via manifest.json:

{
 "entries": [
    {
        "title": "first entry",
        "hide": false,
        "id": 1
    },
    {
        "title": "second entry",
        "hide": true,
        "id": 2
    }
 ]
}

The ComboBox defined inside a FragmentDefinition inside a Popover:

               <ComboBox id="xys" selectedKey="{myModel>/aKey}" value="{myModel>/aValue}"
                    items="{myModel>/entries}">
                    <core:ListItem key="{myModel>id}" text="{path: 'myModel>', formatter: '.entryTextFormatter'}" >
                        <core:customData>
                            <core:CustomData key="hide-item" value="{path: 'myModel>', formatter: '.hideItemFormatter'}" writeToDom="true"/>
                        </core:customData>
                    </core:ListItem>
                </ComboBox>

And the formatter code looks like:

/* Test cases */
entryTextFormatter: function(entry) {
    return entry.title;
},
hideItemFormatter: function(entry) {
    if(entry && (entry.hide == true)) {
        return "true";
    } else {
        return "false";
    }
},

Edit: Note! If using the same formatter for the CustomData and the ListItem it is only called twice for the CustomData.

Does anyone has an idea why the formatter gets null as parameter the second time?

question from:https://stackoverflow.com/questions/65923710/ui5-why-is-the-formatter-called-a-second-time-with-a-null-value

Answer 1

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