Configuration

Methods use the upstream Tom Select settings names in PascalCase. Unset settings are omitted, allowing Tom Select to apply its defaults. Explicit false and null values are preserved.

Category	Fluent methods
Selection	MaxItems, MaxOptions, Mode, Items, HideSelected, Duplicates, AllowEmptyOption, CloseAfterSelect, ClearAfterSelect, SelectOnTab
Creation and paste	Create(bool/string), CreateOnBlur, CreateFilter(string/JavaScript), Persist, AddPrecedence, Delimiter, SplitOn(string/JavaScript)
Search	SearchField, SearchConjunction, SortField, Score, Diacritics, Highlight, Nesting, RefreshThrottle
Data	Options, Optgroups, DataAttr, ValueField, LabelField, DisabledField, OptgroupField, OptgroupValueField, OptgroupLabelField, OptionGroupRegister, LockOptgroupOrder
Loading	DataSource, Load, ShouldLoad, LoadThrottle, Preload, PreloadOnFocus, LoadingClass
Appearance	Placeholder, HidePlaceholder, OpenOnFocus, ShouldOpen, DropdownParent, ControlInput, CopyClassesToDropdown
CSS classes	WrapperClass, ControlClass, DropdownClass, DropdownContentClass, ItemClass, OptionClass
Virtual scrolling	FirstUrl, ShouldLoadMore, Load, Plugins(p => p.VirtualScroll())
HTML	Id, Multiple, Disabled, Required, Attribute, HtmlAttributes, ScriptNonce

MaxItems(null) and MaxOptions(null) remove limits; LoadThrottle(null) disables load throttling. ControlInput(null) disables text entry. Mode accepts single/multi; SearchConjunction accepts and/or. For collection binding use a collection model property or Multiple() on an unbound helper; Mode alone does not change form semantics.

Weighted search and sorting

.SearchField(fields => fields.Add("name", 2).Add("description", 0.5))
.SortField(fields => fields.Add("$score", "desc").Add("name", "asc"))
.SearchConjunction("and")

SearchField() with no arguments disables local filtering, useful with server-ranked results. SortField(new JavaScript("customSort")) accepts an upstream sort function.

Groups

.Optgroups(groups => groups.Add("web", "Web").Add("systems", "Systems"))
.Options(options => options
    .Add("js", "JavaScript", "web")
    .Add("rs", "Rust", "systems")
    .Add("cpp", "C++", "systems", disabled: true))
.LockOptgroupOrder()

For additional option metadata or multiple group membership, use Options(IEnumerable<T>) and supply custom objects. Use the corresponding group mapping methods when your property names differ from Tom Select's defaults.

Callbacks

.Callbacks(callbacks => callbacks
    .OnChange("function(value) { console.log(value); }")
    .OnDelete("function(values) { return confirm('Remove selection?'); }")
    .OnInitialize("onSelectReady"))

Available callbacks: OnInitialize, OnFocus, OnBlur, OnChange, OnItemAdd, OnItemRemove, OnItemSelect, OnClear, OnDelete, OnOptionAdd, OnOptionRemove, OnOptionClear, OnOptionGroupAdd, OnOptionGroupRemove, OnOptionGroupClear, OnDropdownOpen, OnDropdownClose, OnType, OnLoad, OnDestroy. OnItemSelect and OnDestroy are registered through the instance event API after construction and therefore are not included in configuration-only output.

Extension points and executable expressions

.Set("futureOption", new { enabled = true })
.SetJavaScript("customCallback", "myCallback")
.SplitOn(new JavaScript("/[,;]+/"))
.CreateFilter(new JavaScript("function(input) { return input.length > 2; }"))

Import RazorKit.TomSelect for JavaScript. Only callbacks, SetJavaScript, and explicit JavaScript objects emit executable expressions; ordinary strings remain encoded JSON. Never pass untrusted input into executable expressions. HTML script delimiters in raw code are rejected; escape them inside JavaScript string literals if required. Custom render functions must escape displayed data themselves.