#SearchDropdown

A SearchDropdown is a text field with a filtered list of choices under it. Its value is the picked choice. With multi-select, the value is the picked choices joined with ", "; a choice can contain a comma. The choices are ChoiceItems: a row can also show an icon, a detail text (such as a shortcut) and a group, and a choice can be disabled. See Choice items.

<UIToolbox.SearchDropdown label="Asset" placeholder="Search assets..."
    choices="Stone Texture,Grass Texture,Character Model" multi-select="false" />

var assets = new SearchDropdown("Asset") { Choices = assetNames, MultiSelect = true, ShowSelectedCount = true };
assets.SelectionChanged += picked => Debug.Log(string.Join(", ", picked));

// A chip for each picked tag, and a button that clears them all
var tags = new SearchDropdown("Tags") { Choices = tagNames, MultiSelect = true, ShowChips = true, ShowClearButton = true };

// Rows under a header per asset type
assets.GroupOf = name => name.EndsWith("Texture") ? "Textures" : name.EndsWith("Model") ? "Models" : null;

// Matches from a server, 250 ms after the last key
var users = new SearchDropdown("User") { MinSearchLength = 2 };
users.AsyncSearch = async (query, token) => await userService.FindNamesAsync(query, token);

// Rich rows: a group, a detail text on the right, and a disabled choice
var commands = new SearchDropdown("Command")
{
    Items = new List<ChoiceItem>
    {
        new("Open", "Ctrl+O", openIcon, group: "File"),
        new("Print", "Ctrl+P", group: "File", enabled: false),
        new("Undo", "Ctrl+Z", group: "Edit")
    }
};

• Typing opens the list and filters it. Typing is not a value change; only a pick sends a ChangeEvent.
• Up and Down move the highlight, from the keyboard and from a gamepad. Enter picks it. Escape and Tab close the list and restore the field text. With the list closed, a second Escape clears the kept query (KeepQuery), or the selection when the field has the clear button. While the list is closed, Alt+Down opens it and a plain arrow moves the focus.
• A press outside the field and the list closes it.
• With show-chips, the chips show the selection and the text is only for the query. A click on the "×" of a chip removes that choice. Backspace in an empty text removes the last chip. Many chips go to the next line. The value is still the joined text.
• The chip buttons and the clear button are not stops for Tab or a gamepad. With a gamepad, pick a marked choice in the list again to remove it.
• The list is added to the workspace (or the top element of the document), so a window does not clip it.
• The mark shows the first run that contains the query or, for a fuzzy match, each letter. A < in a choice shows as text. The mark color is the USS property --tb-choice-list-match on the popup (tb-choice-list); it must be see-through.
• The groups keep the order of their best match, and the choices keep their order in a group. FilteredItems has the choices in the shown order, without the headers. The keys pass over the headers and the disabled choices. A click on a header or a disabled choice picks nothing.
• AsyncSearch runs when the query has MinSearchLength letters (at least 1). A shorter query shows Choices. While it waits, the list shows "Searching…". A newer query or a close cancels the token of the older search, and its late results are dropped. The results show in their order, with no filter. An exception shows "Search failed" and goes to the console.
• An AsyncSearch result keeps the icon, detail and group of the Items entry with the same text.

#Styling

The rules are in Assets/UIToolbox/Runtime/Resources/UIToolbox/Styles/Controls.uss.

The highlighted row is the ListView selection: .tb-choice-list .unity-collection-view__item--selected. The text and the detail of the highlighted row use --tb-color-accent-text.