SummitUI - Select

Demo

Selected: None

Features

Generic type support (string, enums, objects)
Full keyboard navigation with typeahead
Grouped items with labels
Flexible positioning with collision detection
EditForm integration with validation
Controlled and uncontrolled modes
WCAG compliant with proper ARIA attributes

Installation

bash

dotnet add package SummitUI

Anatomy

Import the components and structure them as follows:

razor

<SelectRoot TValue="string">
    <SelectTrigger TValue="string">
        <SelectValue TValue="string" Placeholder="Select an option..." />
    </SelectTrigger>
    <SelectPortal TValue="string">
        <SelectContent TValue="string">
            <SelectViewport TValue="string">
                <SelectItem TValue="string" Value="@("option-1")">
                    <SelectItemText>Option 1</SelectItemText>
                </SelectItem>
            </SelectViewport>
        </SelectContent>
    </SelectPortal>
</SelectRoot>

Sub-components

SelectRoot<TValue>

Generic root container managing select state.

SelectTrigger<TValue>

Button that opens the dropdown (combobox role).

SelectValue<TValue>

Displays selected value or placeholder text.

SelectPortal<TValue>

Renders content in fixed-position container.

SelectContent<TValue>

Floating listbox panel with positioning.

SelectViewport<TValue>

Scrollable container for items.

SelectItem<TValue>

Selectable option with option role.

SelectItemText

Text content wrapper for items.

SelectGroup<TValue>

Groups related items together.

SelectGroupLabel

Label for a group of items.

API Reference

SelectRoot<TValue>

The root component that manages select state and provides cascading context.

Property	Type	Default	Description
Value	TValue?	null	Controlled selected value
DefaultValue	TValue?	null	Default value (uncontrolled)
ValueChanged	EventCallback<TValue?>	-	Value change callback
ValueExpression	Expression<Func<TValue?>>?	null	For EditForm validation
OnValueChange	EventCallback<TValue?>	-	Alternative value change callback
Open	bool?	null	Controlled open state
DefaultOpen	bool	false	Default open state
OpenChanged	EventCallback<bool>	-	Open state change callback
Disabled	bool	false	Disable entire select
Required	bool	false	For form validation
Invalid	bool	false	For error styling
Name	string?	null	Form field name for hidden input

SelectTrigger<TValue>

Button that opens the dropdown list.

Property	Type	Default	Description
As	string	"button"	HTML element to render
AriaLabel	string?	null	Direct aria-label
AriaLabelledBy	string?	null	ID of external label

SelectValue<TValue>

Displays the selected value or placeholder.

Property	Type	Default	Description
Placeholder	string?	null	Placeholder when no value selected
ChildContent	RenderFragment?	null	Custom content

SelectContent<TValue>

Floating listbox panel with positioning options.

Property	Type	Default	Description
As	string	"div"	HTML element to render
Side	Side	Bottom	Placement side
SideOffset	int	4	Offset from trigger (px)
Align	Align	Start	Alignment along side axis
AlignOffset	int	0	Alignment offset (px)
AvoidCollisions	bool	true	Avoid viewport boundaries
CollisionPadding	int	8	Viewport padding (px)
EscapeKeyBehavior	EscapeKeyBehavior	Close	Escape key behavior
OutsideClickBehavior	OutsideClickBehavior	Close	Outside click behavior
OnInteractOutside	EventCallback	-	Outside click callback
OnEscapeKeyDown	EventCallback	-	Escape key callback

SelectItem<TValue>

Selectable option within the dropdown.

Property	Type	Default	Description
Valuerequired	TValue	-	Value of this item
Key	string?	null	Optional string key for JS interop
Label	string?	null	Label for typeahead and display
Disabled	bool	false	Disable item
OnSelect	EventCallback	-	Selection callback

Enums

Side

csharp

public enum Side
{
    Top,
    Right,
    Bottom,
    Left
}

Align

csharp

public enum Align
{
    Start,
    Center,
    End
}

EscapeKeyBehavior

csharp

public enum EscapeKeyBehavior
{
    Close,
    Ignore
}

OutsideClickBehavior

csharp

public enum OutsideClickBehavior
{
    Close,
    Ignore
}

Examples

Basic String Select

razor

@code {
    private string? selectedFruit;
}

<SelectRoot TValue="string" @bind-Value="selectedFruit">
    <SelectTrigger TValue="string" class="select-trigger">
        <SelectValue TValue="string" Placeholder="Select a fruit..." />
        <span class="select-icon">▼</span>
    </SelectTrigger>
    <SelectPortal TValue="string">
        <SelectContent TValue="string" class="select-content" SideOffset="4">
            <SelectViewport TValue="string" class="select-viewport">
                <SelectItem TValue="string" Value="@("apple")" Label="Apple">
                    <SelectItemText>Apple</SelectItemText>
                </SelectItem>
                <SelectItem TValue="string" Value="@("banana")" Label="Banana">
                    <SelectItemText>Banana</SelectItemText>
                </SelectItem>
                <SelectItem TValue="string" Value="@("cherry")" Label="Cherry">
                    <SelectItemText>Cherry</SelectItemText>
                </SelectItem>
            </SelectViewport>
        </SelectContent>
    </SelectPortal>
</SelectRoot>

<p>Selected: @(selectedFruit ?? "None")</p>

With Enum Values

Use strongly-typed enum values.

razor

@code {
    public enum Priority { Low, Medium, High, Critical }
    private Priority selectedPriority = Priority.Medium;
}

<SelectRoot TValue="Priority" @bind-Value="selectedPriority">
    <SelectTrigger TValue="Priority" class="select-trigger">
        <SelectValue TValue="Priority" Placeholder="Select priority..." />
    </SelectTrigger>
    <SelectPortal TValue="Priority">
        <SelectContent TValue="Priority" class="select-content">
            <SelectViewport TValue="Priority">
                <SelectItem TValue="Priority" Value="Priority.Low" Label="Low">
                    <SelectItemText>Low Priority</SelectItemText>
                </SelectItem>
                <SelectItem TValue="Priority" Value="Priority.Medium" Label="Medium">
                    <SelectItemText>Medium Priority</SelectItemText>
                </SelectItem>
                <SelectItem TValue="Priority" Value="Priority.High" Label="High">
                    <SelectItemText>High Priority</SelectItemText>
                </SelectItem>
                <SelectItem TValue="Priority" Value="Priority.Critical" Label="Critical">
                    <SelectItemText>Critical Priority</SelectItemText>
                </SelectItem>
            </SelectViewport>
        </SelectContent>
    </SelectPortal>
</SelectRoot>

With Complex Objects

Use custom objects as values.

razor

@code {
    public record Country(string Code, string Name);
    
    private List<Country> countries = new()
    {
        new("US", "United States"),
        new("UK", "United Kingdom"),
        new("CA", "Canada"),
        new("AU", "Australia")
    };
    
    private Country? selectedCountry;
}

<SelectRoot TValue="Country" @bind-Value="selectedCountry">
    <SelectTrigger TValue="Country" class="select-trigger">
        <SelectValue TValue="Country" Placeholder="Select a country..." />
    </SelectTrigger>
    <SelectPortal TValue="Country">
        <SelectContent TValue="Country" class="select-content">
            <SelectViewport TValue="Country">
                @foreach (var country in countries)
                {
                    <SelectItem TValue="Country" 
                                Value="country" 
                                Key="@country.Code" 
                                Label="@country.Name">
                        <SelectItemText>@country.Name (@country.Code)</SelectItemText>
                    </SelectItem>
                }
            </SelectViewport>
        </SelectContent>
    </SelectPortal>
</SelectRoot>

Grouped Items

Organize items into logical groups.

razor

<SelectRoot TValue="string" @bind-Value="selectedFood">
    <SelectTrigger TValue="string" class="select-trigger">
        <SelectValue TValue="string" Placeholder="Select food..." />
    </SelectTrigger>
    <SelectPortal TValue="string">
        <SelectContent TValue="string" class="select-content">
            <SelectViewport TValue="string">
                <SelectGroup TValue="string">
                    <SelectGroupLabel class="select-group-label">Fruits</SelectGroupLabel>
                    <SelectItem TValue="string" Value="@("apple")" Label="Apple">
                        <SelectItemText>Apple</SelectItemText>
                    </SelectItem>
                    <SelectItem TValue="string" Value="@("banana")" Label="Banana">
                        <SelectItemText>Banana</SelectItemText>
                    </SelectItem>
                </SelectGroup>
                <SelectGroup TValue="string">
                    <SelectGroupLabel class="select-group-label">Vegetables</SelectGroupLabel>
                    <SelectItem TValue="string" Value="@("carrot")" Label="Carrot">
                        <SelectItemText>Carrot</SelectItemText>
                    </SelectItem>
                    <SelectItem TValue="string" Value="@("broccoli")" Label="Broccoli">
                        <SelectItemText>Broccoli</SelectItemText>
                    </SelectItem>
                </SelectGroup>
            </SelectViewport>
        </SelectContent>
    </SelectPortal>
</SelectRoot>

EditForm Integration

Use with Blazor EditForm for validation.

razor

@code {
    public class FormModel
    {
        [Required(ErrorMessage = "Category is required")]
        public string? Category { get; set; }
    }
    
    private FormModel formModel = new();
    private EditContext? editContext;
    
    protected override void OnInitialized()
    {
        editContext = new EditContext(formModel);
    }
    
    private void HandleSubmit()
    {
        if (editContext!.Validate())
        {
            // Process form
        }
    }
}

<EditForm EditContext="editContext" OnSubmit="HandleSubmit">
    <DataAnnotationsValidator />
    
    <div class="form-field">
        <label for="category">Category</label>
        <SelectRoot TValue="string" 
                    @bind-Value="formModel.Category" 
                    Name="category" 
                    Required="true">
            <SelectTrigger TValue="string" class="select-trigger" id="category">
                <SelectValue TValue="string" Placeholder="Select category..." />
            </SelectTrigger>
            <SelectPortal TValue="string">
                <SelectContent TValue="string" class="select-content">
                    <SelectViewport TValue="string">
                        <SelectItem TValue="string" Value="@("electronics")" Label="Electronics">
                            <SelectItemText>Electronics</SelectItemText>
                        </SelectItem>
                        <SelectItem TValue="string" Value="@("clothing")" Label="Clothing">
                            <SelectItemText>Clothing</SelectItemText>
                        </SelectItem>
                        <SelectItem TValue="string" Value="@("books")" Label="Books">
                            <SelectItemText>Books</SelectItemText>
                        </SelectItem>
                    </SelectViewport>
                </SelectContent>
            </SelectPortal>
        </SelectRoot>
        <ValidationMessage For="@(() => formModel.Category)" />
    </div>
    
    <button type="submit">Submit</button>
</EditForm>

Disabled State

Disable entire select or individual items.

razor

@* Disabled entire select *@
<SelectRoot TValue="string" Disabled="true">
    <SelectTrigger TValue="string" class="select-trigger">
        <SelectValue TValue="string" Placeholder="Disabled..." />
    </SelectTrigger>
    ...
</SelectRoot>

@* Disabled individual items *@
<SelectRoot TValue="string" @bind-Value="selectedValue">
    <SelectTrigger TValue="string" class="select-trigger">
        <SelectValue TValue="string" Placeholder="Select..." />
    </SelectTrigger>
    <SelectPortal TValue="string">
        <SelectContent TValue="string" class="select-content">
            <SelectViewport TValue="string">
                <SelectItem TValue="string" Value="@("option1")" Label="Option 1">
                    <SelectItemText>Option 1</SelectItemText>
                </SelectItem>
                <SelectItem TValue="string" Value="@("option2")" Label="Option 2" Disabled="true">
                    <SelectItemText>Option 2 (Disabled)</SelectItemText>
                </SelectItem>
                <SelectItem TValue="string" Value="@("option3")" Label="Option 3">
                    <SelectItemText>Option 3</SelectItemText>
                </SelectItem>
            </SelectViewport>
        </SelectContent>
    </SelectPortal>
</SelectRoot>

Styling

Data Attributes

Attribute	Values	Description
data-state	"open" \| "closed"	Dropdown open state (on trigger/content)
data-state	"checked" \| "unchecked"	Item selection state
data-highlighted	Present when focused	Item is keyboard-focused
data-disabled	Present when disabled	Item or trigger is disabled
data-placeholder	Present when no value	Showing placeholder text
data-invalid	Present when invalid	For form validation errors

CSS Example

css

.select-trigger {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 200px;
    padding: 8px 12px;
    background: white;
    border: 1px solid #ccc;
    border-radius: 6px;
    cursor: pointer;
}

.select-trigger[data-state="open"] {
    border-color: #0066cc;
    box-shadow: 0 0 0 2px rgba(0, 102, 204, 0.2);
}

.select-trigger[data-disabled] {
    opacity: 0.5;
    cursor: not-allowed;
}

.select-trigger[data-placeholder] {
    color: #999;
}

.select-content {
    background: white;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    overflow: hidden;
}

.select-viewport {
    padding: 4px;
    max-height: 300px;
    overflow-y: auto;
}

.select-item {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    border-radius: 4px;
    cursor: pointer;
}

.select-item[data-highlighted] {
    background: rgb(var(--su-accent));
    color: rgb(var(--su-accent-foreground));
}

.select-item[data-state="checked"] {
    background: #e6f0ff;
}

.select-item[data-disabled] {
    opacity: 0.5;
    cursor: not-allowed;
}

.select-group-label {
    padding: 8px 12px;
    font-size: 12px;
    font-weight: 600;
    color: #666;
    text-transform: uppercase;
}

Accessibility

Keyboard Navigation

Key	Action
Enter / Space	Open dropdown or select highlighted item
ArrowDown	Open dropdown or move to next item
ArrowUp	Move to previous item
Home	Move to first item
End	Move to last item
Escape	Close dropdown
A-Z / a-z	Typeahead - jump to matching item

Typeahead

Typing characters while the dropdown is open will jump to items that match the typed text. The search buffer resets after a short delay.

ARIA Attributes

SelectTrigger: Has role="combobox", aria-haspopup="listbox", and aria-expanded
SelectContent: Has role="listbox"
SelectItem: Has role="option" with aria-selected
SelectGroup: Has role="group" with aria-labelledby
Disabled items: Have aria-disabled

Select LLM

Demo

Features

Installation

Anatomy

Sub-components

SelectRoot<TValue>

SelectTrigger<TValue>

SelectValue<TValue>

SelectPortal<TValue>

SelectContent<TValue>

SelectViewport<TValue>

SelectItem<TValue>

SelectItemText

SelectGroup<TValue>

SelectGroupLabel

API Reference

SelectRoot<TValue>

SelectTrigger<TValue>

SelectValue<TValue>

SelectContent<TValue>

SelectItem<TValue>

Enums

Side

Align

EscapeKeyBehavior

OutsideClickBehavior

Examples

Basic String Select

With Enum Values

With Complex Objects

Grouped Items

EditForm Integration

Disabled State

Styling

Data Attributes

CSS Example

Accessibility

Keyboard Navigation

Typeahead

ARIA Attributes

Select