docs(table): add selection example (#8161)

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Author: andrewseguin

src/material-examples/table-selection/table-selection-example.css

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+.example-container {
+  display: flex;
+  flex-direction: column;
+  max-height: 500px;
+  min-width: 300px;
+}
+
+.mat-table {
+  overflow: auto;
+  max-height: 500px;
+}
+
+.mat-column-select {
+  overflow: initial;
+}

src/material-examples/table-selection/table-selection-example.html

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+<div class="example-container mat-elevation-z8">
+  <mat-table #table [dataSource]="dataSource">
+
+    <!-- Checkbox Column -->
+    <ng-container matColumnDef="select">
+      <mat-header-cell *matHeaderCellDef>
+        <mat-checkbox (change)="$event ? masterToggle() : null"
+                      [checked]="selection.hasValue() && isAllSelected()"
+                      [indeterminate]="selection.hasValue() && !isAllSelected()">
+        </mat-checkbox>
+      </mat-header-cell>
+      <mat-cell *matCellDef="let row">
+        <mat-checkbox (click)="$event.stopPropagation()"
+                      (change)="$event ? selection.toggle(row) : null"
+                      [checked]="selection.isSelected(row)">
+        </mat-checkbox>
+      </mat-cell>
+    </ng-container>
+
+    <!-- Position Column -->
+    <ng-container matColumnDef="position">
+      <mat-header-cell *matHeaderCellDef> No. </mat-header-cell>
+      <mat-cell *matCellDef="let element"> {{element.position}} </mat-cell>
+    </ng-container>
+
+    <!-- Name Column -->
+    <ng-container matColumnDef="name">
+      <mat-header-cell *matHeaderCellDef> Name </mat-header-cell>
+      <mat-cell *matCellDef="let element"> {{element.name}} </mat-cell>
+    </ng-container>
+
+    <!-- Weight Column -->
+    <ng-container matColumnDef="weight">
+      <mat-header-cell *matHeaderCellDef> Weight </mat-header-cell>
+      <mat-cell *matCellDef="let element"> {{element.weight}} </mat-cell>
+    </ng-container>
+
+    <!-- Color Column -->
+    <ng-container matColumnDef="symbol">
+      <mat-header-cell *matHeaderCellDef> Symbol </mat-header-cell>
+      <mat-cell *matCellDef="let element"> {{element.symbol}} </mat-cell>
+    </ng-container>
+
+    <mat-header-row *matHeaderRowDef="displayedColumns"></mat-header-row>
+    <mat-row *matRowDef="let row; columns: displayedColumns;"
+             (click)="selection.toggle(row)">
+    </mat-row>
+  </mat-table>
+</div>

src/material-examples/table-selection/table-selection-example.ts

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+import {Component} from '@angular/core';
+import {MatTableDataSource} from '@angular/material';
+import {SelectionModel} from '@angular/cdk/collections';
+
+/**
+ * @title Table with selection
+ */
+@Component({
+  selector: 'table-selection-example',
+  styleUrls: ['table-selection-example.css'],
+  templateUrl: 'table-selection-example.html',
+})
+export class TableSelectionExample {
+  displayedColumns = ['select', 'position', 'name', 'weight', 'symbol'];
+  dataSource = new MatTableDataSource<Element>(ELEMENT_DATA);
+  selection = new SelectionModel<Element>(true, []);
+
+  /** Whether the number of selected elements matches the total number of rows. */
+  isAllSelected() {
+    const numSelected = this.selection.selected.length;
+    const numRows = this.dataSource.data.length;
+    return numSelected === numRows;
+  }
+
+  /** Selects all rows if they are not all selected; otherwise clear selection. */
+  masterToggle() {
+    this.isAllSelected() ?
+        this.selection.clear() :
+        this.dataSource.data.forEach(row => this.selection.select(row));
+  }
+}
+
+export interface Element {
+  name: string;
+  position: number;
+  weight: number;
+  symbol: string;
+}
+
+const ELEMENT_DATA: Element[] = [
+  {position: 1, name: 'Hydrogen', weight: 1.0079, symbol: 'H'},
+  {position: 2, name: 'Helium', weight: 4.0026, symbol: 'He'},
+  {position: 3, name: 'Lithium', weight: 6.941, symbol: 'Li'},
+  {position: 4, name: 'Beryllium', weight: 9.0122, symbol: 'Be'},
+  {position: 5, name: 'Boron', weight: 10.811, symbol: 'B'},
+  {position: 6, name: 'Carbon', weight: 12.0107, symbol: 'C'},
+  {position: 7, name: 'Nitrogen', weight: 14.0067, symbol: 'N'},
+  {position: 8, name: 'Oxygen', weight: 15.9994, symbol: 'O'},
+  {position: 9, name: 'Fluorine', weight: 18.9984, symbol: 'F'},
+  {position: 10, name: 'Neon', weight: 20.1797, symbol: 'Ne'},
+  {position: 11, name: 'Sodium', weight: 22.9897, symbol: 'Na'},
+  {position: 12, name: 'Magnesium', weight: 24.305, symbol: 'Mg'},
+  {position: 13, name: 'Aluminum', weight: 26.9815, symbol: 'Al'},
+  {position: 14, name: 'Silicon', weight: 28.0855, symbol: 'Si'},
+  {position: 15, name: 'Phosphorus', weight: 30.9738, symbol: 'P'},
+  {position: 16, name: 'Sulfur', weight: 32.065, symbol: 'S'},
+  {position: 17, name: 'Chlorine', weight: 35.453, symbol: 'Cl'},
+  {position: 18, name: 'Argon', weight: 39.948, symbol: 'Ar'},
+  {position: 19, name: 'Potassium', weight: 39.0983, symbol: 'K'},
+  {position: 20, name: 'Calcium', weight: 40.078, symbol: 'Ca'},
+];