feat(select): add multiple selection mode

src/demo-app/select/select-demo.html

@@ -1,23 +1,10 @@
 <div style="height: 1000px">This div is for testing scrolled selects.</div>
 <button md-button (click)="showSelect=!showSelect">SHOW SELECT</button>
 <div class="demo-select">
-  <div *ngIf="showSelect">
-    <md-card>
-      <md-select placeholder="Food i would like to eat" [formControl]="foodControl">
-        <md-option *ngFor="let food of foods" [value]="food.value"> {{ food.viewValue }} </md-option>
-      </md-select>
-      <p> Value: {{ foodControl.value }} </p>
-      <p> Touched: {{ foodControl.touched }} </p>
-      <p> Dirty: {{ foodControl.dirty }} </p>
-      <p> Status: {{ foodControl.status }} </p>
-      <button md-button (click)="foodControl.setValue('pizza-1')">SET VALUE</button>
-      <button md-button (click)="toggleDisabled()">TOGGLE DISABLED</button>
-      <button md-button (click)="foodControl.reset()">RESET</button>
-    </md-card>
-  </div>
-
   <md-card>
-    <md-select placeholder="Drink" [(ngModel)]="currentDrink" [required]="isRequired" [disabled]="isDisabled"
+    <md-card-subtitle>ngModel</md-card-subtitle>
+
+    <md-select placeholder="Drink" [(ngModel)]="currentDrink" [required]="drinksRequired" [disabled]="drinksDisabled"
       [floatPlaceholder]="floatPlaceholder" #drinkControl="ngModel">
       <md-option *ngFor="let drink of drinks" [value]="drink.value" [disabled]="drink.disabled">
         {{ drink.viewValue }}
@@ -37,18 +24,62 @@
     </p>
 
     <button md-button (click)="currentDrink='water-2'">SET VALUE</button>
-    <button md-button (click)="isRequired=!isRequired">TOGGLE REQUIRED</button>
-    <button md-button (click)="isDisabled=!isDisabled">TOGGLE DISABLED</button>
+    <button md-button (click)="drinksRequired=!drinksRequired">TOGGLE REQUIRED</button>
+    <button md-button (click)="drinksDisabled=!drinksDisabled">TOGGLE DISABLED</button>
     <button md-button (click)="drinkControl.reset()">RESET</button>
   </md-card>
 
+  <md-card>
+    <md-card-subtitle>Multiple selection</md-card-subtitle>
+
+    <md-card-content>
+      <md-select multiple placeholder="Pokemon" [(ngModel)]="currentPokemon"
+        [required]="pokemonRequired" [disabled]="pokemonDisabled" #pokemonControl="ngModel">
+        <md-option *ngFor="let creature of pokemon" [value]="creature.value">
+          {{ creature.viewValue }}
+        </md-option>
+      </md-select>
+      <p> Value: {{ currentPokemon }} </p>
+      <p> Touched: {{ pokemonControl.touched }} </p>
+      <p> Dirty: {{ pokemonControl.dirty }} </p>
+      <p> Status: {{ pokemonControl.control?.status }} </p>
+      <button md-button (click)="setPokemonValue()">SET VALUE</button>
+      <button md-button (click)="pokemonRequired=!pokemonRequired">TOGGLE REQUIRED</button>
+      <button md-button (click)="pokemonDisabled=!pokemonDisabled">TOGGLE DISABLED</button>
+      <button md-button (click)="pokemonControl.reset()">RESET</button>
+    </md-card-content>
+  </md-card>
+
   <div *ngIf="showSelect">
     <md-card>
-      <md-select placeholder="Starter Pokemon" (change)="latestChangeEvent = $event">
-        <md-option *ngFor="let starter of pokemon" [value]="starter.value"> {{ starter.viewValue }} </md-option>
-      </md-select>
+      <md-card-subtitle>formControl</md-card-subtitle>
+
+      <md-card-content>
+        <md-select placeholder="Food i would like to eat" [formControl]="foodControl">
+          <md-option *ngFor="let food of foods" [value]="food.value"> {{ food.viewValue }}</md-option>
+        </md-select>
+        <p> Value: {{ foodControl.value }} </p>
+        <p> Touched: {{ foodControl.touched }} </p>
+        <p> Dirty: {{ foodControl.dirty }} </p>
+        <p> Status: {{ foodControl.status }} </p>
+        <button md-button (click)="foodControl.setValue('pizza-1')">SET VALUE</button>
+        <button md-button (click)="toggleDisabled()">TOGGLE DISABLED</button>
+        <button md-button (click)="foodControl.reset()">RESET</button>
+      </md-card-content>
+    </md-card>
+  </div>
+
+  <div *ngIf="showSelect">
+    <md-card>
+      <md-card-subtitle>Change event</md-card-subtitle>
+
+      <md-card-content>
+        <md-select placeholder="Starter Pokemon" (change)="latestChangeEvent = $event">
+          <md-option *ngFor="let creature of pokemon" [value]="creature.value">{{ creature.viewValue }}</md-option>
+        </md-select>
 
-      <p> Change event value: {{ latestChangeEvent?.value }} </p>
+        <p> Change event value: {{ latestChangeEvent?.value }} </p>
+      </md-card-content>
     </md-card>
   </div>
 

src/demo-app/select/select-demo.ts

@@ -9,10 +9,13 @@ import {MdSelectChange} from '@angular/material';
     styleUrls: ['select-demo.css'],
 })
 export class SelectDemo {
-  isRequired = false;
-  isDisabled = false;
+  drinksRequired = false;
+  pokemonRequired = false;
+  drinksDisabled = false;
+  pokemonDisabled = false;
   showSelect = false;
   currentDrink: string;
+  currentPokemon: string[];
   latestChangeEvent: MdSelectChange;
   floatPlaceholder: string = 'auto';
   foodControl = new FormControl('pizza-1');
@@ -38,10 +41,18 @@ export class SelectDemo {
   pokemon = [
     {value: 'bulbasaur-0', viewValue: 'Bulbasaur'},
     {value: 'charizard-1', viewValue: 'Charizard'},
-    {value: 'squirtle-2', viewValue: 'Squirtle'}
+    {value: 'squirtle-2', viewValue: 'Squirtle'},
+    {value: 'pikachu-3', viewValue: 'Pikachu'},
+    {value: 'eevee-4', viewValue: 'Eevee'},
+    {value: 'ditto-5', viewValue: 'Ditto'},
+    {value: 'psyduck-6', viewValue: 'Psyduck'},
   ];
 
   toggleDisabled() {
     this.foodControl.enabled ? this.foodControl.disable() : this.foodControl.enable();
   }
+
+  setPokemonValue() {
+    this.currentPokemon = ['eevee-4', 'psyduck-6'];
+  }
 }

src/lib/autocomplete/autocomplete-trigger.ts

@@ -15,7 +15,7 @@ import {MdAutocomplete} from './autocomplete';
 import {PositionStrategy} from '../core/overlay/position/position-strategy';
 import {ConnectedPositionStrategy} from '../core/overlay/position/connected-position-strategy';
 import {Observable} from 'rxjs/Observable';
-import {MdOptionSelectEvent, MdOption} from '../core/option/option';
+import {MdOptionSelectionChange, MdOption} from '../core/option/option';
 import {ENTER, UP_ARROW, DOWN_ARROW} from '../core/keyboard/keycodes';
 import {Dir} from '../core/rtl/dir';
 import {Subscription} from 'rxjs/Subscription';
@@ -146,7 +146,7 @@ export class MdAutocompleteTrigger implements ControlValueAccessor, OnDestroy {
    * A stream of actions that should close the autocomplete panel, including
    * when an option is selected, on blur, and when TAB is pressed.
    */
-  get panelClosingActions(): Observable<MdOptionSelectEvent> {
+  get panelClosingActions(): Observable<MdOptionSelectionChange> {
     return Observable.merge(
         this.optionSelections,
         this._blurStream.asObservable(),
@@ -155,8 +155,8 @@ export class MdAutocompleteTrigger implements ControlValueAccessor, OnDestroy {
   }
 
   /** Stream of autocomplete option selections. */
-  get optionSelections(): Observable<MdOptionSelectEvent> {
-    return Observable.merge(...this.autocomplete.options.map(option => option.onSelect));
+  get optionSelections(): Observable<MdOptionSelectionChange> {
+    return Observable.merge(...this.autocomplete.options.map(option => option.onSelectionChange));
   }
 
   /** The currently active option, coerced to MdOption type. */
@@ -301,7 +301,7 @@ export class MdAutocompleteTrigger implements ControlValueAccessor, OnDestroy {
    * control to that value. It will also mark the control as dirty if this interaction
    * stemmed from the user.
    */
-  private _setValueAndClose(event: MdOptionSelectEvent | null): void {
+  private _setValueAndClose(event: MdOptionSelectionChange | null): void {
     if (event) {
       this._setTriggerValue(event.source.value);
       this._onChange(event.source.value);

src/lib/core/option/_option-theme.scss

@@ -12,8 +12,12 @@
     }
 
     &.mat-selected {
-      background: mat-color($background, hover);
       color: mat-color($primary);
+
+      // In multiple mode there is a checkbox to show that the option is selected.
+      &:not(.mat-option-multiple) {
+        background: mat-color($background, hover);
+      }
     }
 
     &.mat-active {
@@ -26,4 +30,4 @@
     }
 
   }
-}
+}

src/lib/core/option/_option.scss

@@ -30,5 +30,15 @@
       opacity: 0.5;
     }
   }
+
+  .mat-option-pseudo-checkbox {
+    $margin: $mat-menu-side-padding / 2;
+    margin-right: $margin;
+
+    [dir='rtl'] & {
+      margin-left: $margin;
+      margin-right: 0;
+    }
+  }
 }
 

src/lib/core/option/option.html

@@ -1,3 +1,10 @@
+<span [ngSwitch]="_isCompatibilityMode" *ngIf="multiple">
+  <mat-pseudo-checkbox class="mat-option-pseudo-checkbox" *ngSwitchCase="true"
+      [state]="selected ? 'checked' : ''" color="primary"></mat-pseudo-checkbox>
+  <md-pseudo-checkbox class="mat-option-pseudo-checkbox" *ngSwitchDefault
+      [state]="selected ? 'checked' : ''" color="primary"></md-pseudo-checkbox>
+</span>
+
 <ng-content></ng-content>
 <div class="mat-option-ripple" *ngIf="!disabled" md-ripple [mdRippleTrigger]="_getHostElement()">
 </div>

src/lib/core/option/option.ts

@@ -7,22 +7,26 @@ import {
   NgModule,
   ModuleWithProviders,
   Renderer,
-  ViewEncapsulation
+  ViewEncapsulation,
+  Inject,
+  Optional,
 } from '@angular/core';
 import {CommonModule} from '@angular/common';
 import {ENTER, SPACE} from '../keyboard/keycodes';
 import {coerceBooleanProperty} from '../coercion/boolean-property';
 import {MdRippleModule} from '../ripple/index';
+import {MdSelectionModule} from '../selection/index';
+import {MATERIAL_COMPATIBILITY_MODE} from '../../core/compatibility/compatibility';
 
 /**
  * Option IDs need to be unique across components, so this counter exists outside of
  * the component definition.
  */
 let _uniqueIdCounter = 0;
 
-/** Event object emitted by MdOption when selected. */
-export class MdOptionSelectEvent {
-  constructor(public source: MdOption, public isUserInput = false) {}
+/** Event object emitted by MdOption when selected or deselected. */
+export class MdOptionSelectionChange {
+  constructor(public source: MdOption, public isUserInput = false) { }
 }
 
 
@@ -36,6 +40,7 @@ export class MdOptionSelectEvent {
     'role': 'option',
     '[attr.tabindex]': '_getTabIndex()',
     '[class.mat-selected]': 'selected',
+    '[class.mat-option-multiple]': 'multiple',
     '[class.mat-active]': 'active',
     '[id]': 'id',
     '[attr.aria-selected]': 'selected.toString()',
@@ -57,9 +62,15 @@ export class MdOption {
 
   private _id: string = `md-option-${_uniqueIdCounter++}`;
 
+  /** Whether the wrapping component is in multiple selection mode. */
+  multiple: boolean = false;
+
   /** The unique ID of the option. */
   get id() { return this._id; }
 
+  /** Whether or not the option is currently selected. */
+  get selected(): boolean { return this._selected; }
+
   /** The form value of the option. */
   @Input() value: any;
 
@@ -68,15 +79,13 @@ export class MdOption {
   get disabled() { return this._disabled; }
   set disabled(value: any) { this._disabled = coerceBooleanProperty(value); }
 
-  /** Event emitted when the option is selected. */
-  @Output() onSelect = new EventEmitter<MdOptionSelectEvent>();
+  /** Event emitted when the option is selected or deselected. */
+  @Output() onSelectionChange = new EventEmitter<MdOptionSelectionChange>();
 
-  constructor(private _element: ElementRef, private _renderer: Renderer) {}
-
-  /** Whether or not the option is currently selected. */
-  get selected(): boolean {
-    return this._selected;
-  }
+  constructor(
+    private _element: ElementRef,
+    private _renderer: Renderer,
+    @Optional() @Inject(MATERIAL_COMPATIBILITY_MODE) public _isCompatibilityMode: boolean) {}
 
   /**
    * Whether or not the option is currently active and ready to be selected.
@@ -100,12 +109,13 @@ export class MdOption {
   /** Selects the option. */
   select(): void {
     this._selected = true;
-    this.onSelect.emit(new MdOptionSelectEvent(this, false));
+    this._emitSelectionChangeEvent();
   }
 
   /** Deselects the option. */
   deselect(): void {
     this._selected = false;
+    this._emitSelectionChangeEvent();
   }
 
   /** Sets focus onto this option. */
@@ -118,7 +128,7 @@ export class MdOption {
    * active. This is used by the ActiveDescendantKeyManager so key
    * events will display the proper options as active on arrow key events.
    */
-  setActiveStyles() {
+  setActiveStyles(): void {
     Promise.resolve(null).then(() => this._active = true);
   }
 
@@ -127,7 +137,7 @@ export class MdOption {
    * active. This is used by the ActiveDescendantKeyManager so key
    * events will display the proper options as active on arrow key events.
    */
-  setInactiveStyles() {
+  setInactiveStyles(): void {
     Promise.resolve(null).then(() => this._active = false);
   }
 
@@ -142,26 +152,32 @@ export class MdOption {
    * Selects the option while indicating the selection came from the user. Used to
    * determine if the select's view -> model callback should be invoked.
    */
-  _selectViaInteraction() {
+  _selectViaInteraction(): void {
     if (!this.disabled) {
-      this._selected = true;
-      this.onSelect.emit(new MdOptionSelectEvent(this, true));
+      this._selected = this.multiple ? !this._selected : true;
+      this._emitSelectionChangeEvent(true);
     }
   }
 
   /** Returns the correct tabindex for the option depending on disabled state. */
-  _getTabIndex() {
+  _getTabIndex(): string {
     return this.disabled ? '-1' : '0';
   }
 
+  /** Fetches the host DOM element. */
   _getHostElement(): HTMLElement {
     return this._element.nativeElement;
   }
 
+  /** Emits the selection change event. */
+  private _emitSelectionChangeEvent(isUserInput = false): void {
+    this.onSelectionChange.emit(new MdOptionSelectionChange(this, isUserInput));
+  };
+
 }
 
 @NgModule({
-  imports: [MdRippleModule, CommonModule],
+  imports: [MdRippleModule, CommonModule, MdSelectionModule],
   exports: [MdOption],
   declarations: [MdOption]
 })

src/lib/core/selection/pseudo-checkbox/_pseudo-checkbox-theme.scss

@@ -24,8 +24,6 @@
   }
 
   .mat-pseudo-checkbox-checked, .mat-pseudo-checkbox-indeterminate {
-    border: none;
-
     &.mat-primary {
       background: mat-color($primary, 500);
     }