blocks|key|3421267|text|原来，我从multiTemplateDataRows标签中丢失了指令<table>：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3421268|<table+mat-table+[dataSource]="licenses"+multiTemplateDataRows>|code-block|syntax|javascript|3421269|entityMap^0|5|L|Y|7|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|L|$]]

It turns out I was missing directive <code>multiTemplateDataRows</code> from <code>&lt;table&gt;</code> tag:
<pre class="lang-html prettyprint-override"><code>&lt;table mat-table [dataSource]=&quot;licenses&quot; multiTemplateDataRows&gt;
</code></pre>

blocks|key|2371171|text|我也有同样的问题。我将“角/克&@角/材料”更新为6.4.7。一切都很好。当然，你也需要multiTemplateDataRows|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2371172|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

i had same problem. i updated @angular/cdk &amp; @angular/material to 6.4.7. And all work fine. Of course you need multiTemplateDataRows attr as well

blocks|key|2371182|text|如果when谓词中的函数未定义，也可能出现此错误。所以如果你有|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2371183|<mat-tree-node+*matTreeNodeDef="let+node;+when:+hasChild">|code-block|syntax|javascript|2371184|而hasChild是未定义的，您可能会得到这个错误。|2371185|entityMap^0|2|4|0|0|1|8|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|R|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|V|8|@]|D|@]|E|$]]]|N|$]]

This error could also appear if the function in your <code>when</code> predicate is undefined. So if you have
<pre class="lang-html prettyprint-override"><code>&lt;mat-tree-node *matTreeNodeDef=&quot;let node; when: hasChild&quot;&gt;
</code></pre>
and <code>hasChild</code> is undefined, you could get that error.

blocks|key|3662114|text|就像这样：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3662115|wrapper-table.ts|3662116|import+{+SelectionModel+}+from+'@angular/cdk/collections';
import+{+AfterContentInit,+Component,+ContentChildren,+Input,+QueryList,+TemplateRef,+ViewChild+}+from+'@angular/core';
import+{+MatColumnDef,+MatHeaderRowDef,+MatRowDef,+MatTable,+MatTableDataSource+}+from+'@angular/material/table';

@Component({
++selector:+'ui-wrapper-table',
++templateUrl:+'./wrapper-table.component.html',
++styleUrls:+['./wrapper-table.component.scss']
})
export+class+WrapperTable<T>+implements+AfterContentInit+{

++@ContentChildren(MatHeaderRowDef)+headerRowDefs:+QueryList<MatHeaderRowDef>;
++@ContentChildren(MatRowDef)+rowDefs:+QueryList<MatRowDef<T>>;
++@ContentChildren(MatColumnDef)+columnDefs:+QueryList<MatColumnDef>;

++@ViewChild(MatTable,+{+static:+true+})+table:+MatTable<T>;

++@Input()+columns:+string[];

++@Input()+dataSource:+MatTableDataSource<T>;

++@Input()+contextTemplate:+TemplateRef<any>;

++@Input()+selection:+SelectionModel<T>;

++ngAfterContentInit()+{
++++this.columnDefs.forEach(columnDef+=>+this.table.addColumnDef(columnDef));
++++this.rowDefs.forEach(rowDef+=>+this.table.addRowDef(rowDef));
++++this.headerRowDefs.forEach(headerRowDef+=>+this.table.addHeaderRowDef(headerRowDef));
++}

++isAllSelected()+{
++++const+numSelected+=+this.selection+&&+this.selection.selected.length+%7C%7C+0;
++++const+numRows+=+this.dataSource+&&+this.dataSource.data.length+%7C%7C+0;
++++return+numSelected+===+numRows;
++}
++masterToggle()+{
++++this.isAllSelected()+?
++++++this.selection.clear()+:
++++++this.dataSource.data.forEach(row+=>+this.selection.select(row));
++}
++checkboxLabel(row?:+T):+string+{
++++if+(!row)+{
++++++return+`${this.isAllSelected()+?+'select'+:+'deselect'}+all`;
++++}
++++return+`${this.selection.isSelected(row)+?+'deselect'+:+'select'}+row`;
++}
}|code-block|syntax|javascript|3662117|wrapper-table.html|3662118|<table+mat-table+[dataSource]="dataSource"+class="mat-elevation-z8">
++<ng-content></ng-content>


++
++<ng-container+matColumnDef="select">
++++<th+mat-header-cell+*matHeaderCellDef>
++++++<mat-checkbox+(change)="$event+?+masterToggle()+:+null"+[checked]="selection?.hasValue()+&&+isAllSelected()"
++++++++[indeterminate]="selection?.hasValue()+&&+!isAllSelected()"+[aria-label]="checkboxLabel()">
++++++</mat-checkbox>
++++</th>
++++<td+mat-cell+*matCellDef="let+row">
++++++<mat-checkbox+(click)="$event.stopPropagation()"+(change)="$event+?+selection.toggle(row)+:+null"
++++++++[checked]="selection?.isSelected(row)"+[aria-label]="checkboxLabel(row)">
++++++</mat-checkbox>
++++</td>
++</ng-container>

++
++<ng-container+matColumnDef="id">
++++<th+mat-header-cell+*matHeaderCellDef+mat-sort-header>+#+</th>
++++<td+mat-cell+*matCellDef="let+element">+{{element.id}}+</td>
++</ng-container>

++
++<ng-container+matColumnDef="created">
++++<th+mat-header-cell+*matHeaderCellDef+mat-sort-header>+Criação+</th>
++++<td+mat-cell+*matCellDef="let+element">+{{element.created.toDate()+%7C+date}}+</td>
++</ng-container>

++
++<ng-container+matColumnDef="context">
++++<th+mat-header-cell+*matHeaderCellDef>+Contexto+</th>
++++<td+mat-cell+*matCellDef="let+element">
++++++<ng-container+*ngTemplateOutlet="contextTemplate;context:{row:element}"></ng-container>
++++</td>
++</ng-container>
</table>|3662119|companies.component.ts|3662120|import+{+SelectionModel+}+from+'@angular/cdk/collections';
import+{+Component,+OnDestroy,+OnInit,+ViewChild+}+from+'@angular/core';
import+{+MatSort,+MatTableDataSource+}+from+'@angular/material';
import+{+CompanyModel,+GetAllCompaniesUsecase+}+from+'@apps-waves/core';
import+{+Subject+}+from+'rxjs';
import+{+takeUntil+}+from+'rxjs/operators';


@Component({
++selector:+'wave-companies',
++templateUrl:+'./companies.component.html',
++styleUrls:+['./companies.component.scss']
})
export+class+CompaniesComponent+implements+OnInit,+OnDestroy+{
++displayedColumns:+string[]+=+['select',+'name',+'companyType',+'created',+'context'];
++dataSource:+MatTableDataSource<CompanyModel>;
++selection:+SelectionModel<CompanyModel>;

++@ViewChild('sort',+{+static:+false+})+sort:+MatSort;

++onDestroy+=+new+Subject<void>();


++constructor(
++++private+getAllCompanies:+GetAllCompaniesUsecase
++)+{+}

++ngOnInit()+{
++++this.getAllCompanies.execute()
++++++.pipe(takeUntil(this.onDestroy))
++++++.subscribe(companies+=>+{
++++++++this.dataSource+=+new+MatTableDataSource(companies);
++++++++this.selection+=+new+SelectionModel<CompanyModel>(true,+[]);
++++++++this.dataSource.sort+=+this.sort;
++++++})
++}

++onClick(company:+CompanyModel)+{
++++console.log(company);
++}
++ngOnDestroy()+{
++++this.onDestroy.next();
++++this.onDestroy.complete();
++}
}|3662121|companies.html|3662122|<ui-wrapper-table
++[dataSource]="dataSource"
++[columns]="displayedColumns"
++[selection]="selection"
++matSort+#sort="matSort"
++[contextTemplate]="rowContext">

++
++<ng-container+matColumnDef="name">
++++<th+mat-header-cell+*matHeaderCellDef>+Name+</th>
++++<td+mat-cell+*matCellDef="let+element">+{{element.name}}+</td>
++</ng-container>

++<ng-container+matColumnDef="companyType">
++++<th+mat-header-cell+*matHeaderCellDef>+Segmento+</th>
++++<td+mat-cell+*matCellDef="let+element">+{{element.companyType}}+</td>
++</ng-container>

++
++<tr+mat-header-row+*matHeaderRowDef="displayedColumns;+sticky:+true"></tr>
++<tr+mat-row+*matRowDef="let+row;+columns:+displayedColumns;+"></tr>
</ui-wrapper-table>

<ng-template+#rowContext+let-element="row">
++<button+type="button"+mat-icon-button+(click)="onClick(element)">
++++<mat-icon>edit</mat-icon>
++</button>
</ng-template>

<pre>{{selection?.selected+%7C+json}}</pre>|3662123|它的工作很酷|3662124|entityMap^0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Z|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|11|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|12|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|14|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|15|8|@]|9|@]|A|$]]|$1|S|3|T|5|F|7|16|8|@]|9|@]|A|$G|H]]|$1|U|3|V|5|6|7|17|8|@]|9|@]|A|$]]|$1|W|3|-4|5|6|7|18|8|@]|9|@]|A|$]]]|X|$]]

Try like this:

wrapper-table.ts

<pre class="lang-js prettyprint-override"><code>import { SelectionModel } from '@angular/cdk/collections';
import { AfterContentInit, Component, ContentChildren, Input, QueryList, TemplateRef, ViewChild } from '@angular/core';
import { MatColumnDef, MatHeaderRowDef, MatRowDef, MatTable, MatTableDataSource } from '@angular/material/table';

@Component({
 selector: 'ui-wrapper-table',
 templateUrl: './wrapper-table.component.html',
 styleUrls: ['./wrapper-table.component.scss']
})
export class WrapperTable&lt;T&gt; implements AfterContentInit {

 @ContentChildren(MatHeaderRowDef) headerRowDefs: QueryList&lt;MatHeaderRowDef&gt;;
 @ContentChildren(MatRowDef) rowDefs: QueryList&lt;MatRowDef&lt;T&gt;&gt;;
 @ContentChildren(MatColumnDef) columnDefs: QueryList&lt;MatColumnDef&gt;;

 @ViewChild(MatTable, { static: true }) table: MatTable&lt;T&gt;;

 @Input() columns: string[];

 @Input() dataSource: MatTableDataSource&lt;T&gt;;

 @Input() contextTemplate: TemplateRef&lt;any&gt;;

 @Input() selection: SelectionModel&lt;T&gt;;

 ngAfterContentInit() {
 this.columnDefs.forEach(columnDef =&gt; this.table.addColumnDef(columnDef));
 this.rowDefs.forEach(rowDef =&gt; this.table.addRowDef(rowDef));
 this.headerRowDefs.forEach(headerRowDef =&gt; this.table.addHeaderRowDef(headerRowDef));
 }

 isAllSelected() {
 const numSelected = this.selection &amp;&amp; this.selection.selected.length || 0;
 const numRows = this.dataSource &amp;&amp; this.dataSource.data.length || 0;
 return numSelected === numRows;
 }
 masterToggle() {
 this.isAllSelected() ?
 this.selection.clear() :
 this.dataSource.data.forEach(row =&gt; this.selection.select(row));
 }
 checkboxLabel(row?: T): string {
 if (!row) {
 return `${this.isAllSelected() ? 'select' : 'deselect'} all`;
 }
 return `${this.selection.isSelected(row) ? 'deselect' : 'select'} row`;
 }
}
</code></pre>

wrapper-table.html

<pre class="lang-html prettyprint-override"><code>&lt;table mat-table [dataSource]="dataSource" class="mat-elevation-z8"&gt;
 &lt;ng-content&gt;&lt;/ng-content&gt;


 &lt;!-- Select Column --&gt;
 &lt;ng-container matColumnDef="select"&gt;
 &lt;th mat-header-cell *matHeaderCellDef&gt;
 &lt;mat-checkbox (change)="$event ? masterToggle() : null" [checked]="selection?.hasValue() &amp;&amp; isAllSelected()"
 [indeterminate]="selection?.hasValue() &amp;&amp; !isAllSelected()" [aria-label]="checkboxLabel()"&gt;
 &lt;/mat-checkbox&gt;
 &lt;/th&gt;
 &lt;td mat-cell *matCellDef="let row"&gt;
 &lt;mat-checkbox (click)="$event.stopPropagation()" (change)="$event ? selection.toggle(row) : null"
 [checked]="selection?.isSelected(row)" [aria-label]="checkboxLabel(row)"&gt;
 &lt;/mat-checkbox&gt;
 &lt;/td&gt;
 &lt;/ng-container&gt;

 &lt;!-- Id Column --&gt;
 &lt;ng-container matColumnDef="id"&gt;
 &lt;th mat-header-cell *matHeaderCellDef mat-sort-header&gt; # &lt;/th&gt;
 &lt;td mat-cell *matCellDef="let element"&gt; {{element.id}} &lt;/td&gt;
 &lt;/ng-container&gt;

 &lt;!-- Created Column --&gt;
 &lt;ng-container matColumnDef="created"&gt;
 &lt;th mat-header-cell *matHeaderCellDef mat-sort-header&gt; Criação &lt;/th&gt;
 &lt;td mat-cell *matCellDef="let element"&gt; {{element.created.toDate() | date}} &lt;/td&gt;
 &lt;/ng-container&gt;

 &lt;!-- Context Column --&gt;
 &lt;ng-container matColumnDef="context"&gt;
 &lt;th mat-header-cell *matHeaderCellDef&gt; Contexto &lt;/th&gt;
 &lt;td mat-cell *matCellDef="let element"&gt;
 &lt;ng-container *ngTemplateOutlet="contextTemplate;context:{row:element}"&gt;&lt;/ng-container&gt;
 &lt;/td&gt;
 &lt;/ng-container&gt;
&lt;/table&gt;
</code></pre>

companies.component.ts

<pre class="lang-js prettyprint-override"><code>import { SelectionModel } from '@angular/cdk/collections';
import { Component, OnDestroy, OnInit, ViewChild } from '@angular/core';
import { MatSort, MatTableDataSource } from '@angular/material';
import { CompanyModel, GetAllCompaniesUsecase } from '@apps-waves/core';
import { Subject } from 'rxjs';
import { takeUntil } from 'rxjs/operators';


@Component({
 selector: 'wave-companies',
 templateUrl: './companies.component.html',
 styleUrls: ['./companies.component.scss']
})
export class CompaniesComponent implements OnInit, OnDestroy {
 displayedColumns: string[] = ['select', 'name', 'companyType', 'created', 'context'];
 dataSource: MatTableDataSource&lt;CompanyModel&gt;;
 selection: SelectionModel&lt;CompanyModel&gt;;

 @ViewChild('sort', { static: false }) sort: MatSort;

 onDestroy = new Subject&lt;void&gt;();


 constructor(
 private getAllCompanies: GetAllCompaniesUsecase
 ) { }

 ngOnInit() {
 this.getAllCompanies.execute()
 .pipe(takeUntil(this.onDestroy))
 .subscribe(companies =&gt; {
 this.dataSource = new MatTableDataSource(companies);
 this.selection = new SelectionModel&lt;CompanyModel&gt;(true, []);
 this.dataSource.sort = this.sort;
 })
 }

 onClick(company: CompanyModel) {
 console.log(company);
 }
 ngOnDestroy() {
 this.onDestroy.next();
 this.onDestroy.complete();
 }
}
</code></pre>

companies.html

<pre><code>&lt;ui-wrapper-table
 [dataSource]="dataSource"
 [columns]="displayedColumns"
 [selection]="selection"
 matSort #sort="matSort"
 [contextTemplate]="rowContext"&gt;

 &lt;!-- Custom column definition to be provided to the wrapper table. --&gt;
 &lt;ng-container matColumnDef="name"&gt;
 &lt;th mat-header-cell *matHeaderCellDef&gt; Name &lt;/th&gt;
 &lt;td mat-cell *matCellDef="let element"&gt; {{element.name}} &lt;/td&gt;
 &lt;/ng-container&gt;

 &lt;ng-container matColumnDef="companyType"&gt;
 &lt;th mat-header-cell *matHeaderCellDef&gt; Segmento &lt;/th&gt;
 &lt;td mat-cell *matCellDef="let element"&gt; {{element.companyType}} &lt;/td&gt;
 &lt;/ng-container&gt;

 &lt;!-- Custom row definitions to be provided to the wrapper table. --&gt;
 &lt;tr mat-header-row *matHeaderRowDef="displayedColumns; sticky: true"&gt;&lt;/tr&gt;
 &lt;tr mat-row *matRowDef="let row; columns: displayedColumns; "&gt;&lt;/tr&gt;
&lt;/ui-wrapper-table&gt;

&lt;ng-template #rowContext let-element="row"&gt;
 &lt;button type="button" mat-icon-button (click)="onClick(element)"&gt;
 &lt;mat-icon&gt;edit&lt;/mat-icon&gt;
 &lt;/button&gt;
&lt;/ng-template&gt;

&lt;pre&gt;{{selection?.selected | json}}&lt;/pre&gt;
</code></pre>

Its working pretty cool

blocks|key|3662139|text|你的模板|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3662140|mat-tree-node(*matTreeNodeDef="let+node;when:+hasChild",+matTreeNodePadding)|code-block|syntax|javascript|3662141|您的组件应该有一个名为hasChild的方法|offset|length|style|CODE|3662142|hasChild+=+(_:+number,+node:+FlatNode)+=>+node.expandable;|3662143|entityMap^0|0|0|B|8|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|R|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|S|8|@$I|T|J|U|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|V|8|@]|9|@]|A|$E|F]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

Your template

<pre><code>mat-tree-node(*matTreeNodeDef="let node;when: hasChild", matTreeNodePadding)
</code></pre>

and your component should have a method called <code>hasChild</code>

<pre><code>hasChild = (_: number, node: FlatNode) =&gt; node.expandable;
</code></pre>

I'm trying to implement the <code>Table with expandable rows</code> from <a href="https://material.angular.io/components/table/examples" rel="noreferrer">https://material.angular.io/components/table/examples</a> but I get this error:

<code>There can only be one default row without a when predicate function.</code>

This error comes from the fact that I have two <code>&lt;tr mat-row ...</code>, both without a when predicate (as per example). If I remove one, then the error disappears.

From my own investigation I've found that this feature is new to Material. I upgraded to @angular/material@latest and @angular/cdk@latest and I still got the error.

Does anyone know what I have to do to implement the table as in the example from documentation? <a href="https://material.angular.io/components/table/examples" rel="noreferrer">https://material.angular.io/components/table/examples</a>

My versions:

<pre><code>Angular CLI: 6.0.8
Node: 8.11.2
OS: win32 x64
Angular: 6.0.4
... animations, common, compiler, compiler-cli, core, forms
... http, language-service, platform-browser
... platform-browser-dynamic, router

Package Version
-----------------------------------------------------------
@angular-devkit/architect 0.6.8
@angular-devkit/build-angular 0.6.8
@angular-devkit/build-optimizer 0.6.8
@angular-devkit/core 0.6.8
@angular-devkit/schematics 0.6.8
@angular/cdk 6.3.1
@angular/cli 6.0.8
@angular/flex-layout 6.0.0-beta.16
@angular/material 6.3.1
@ngtools/webpack 6.0.8
@schematics/angular 0.6.8
@schematics/update 0.6.8
rxjs 6.2.0
typescript 2.7.2
webpack 4.8.3
</code></pre>

Angular6 Material6 Error: "There can only be one default row without a when predicate function."

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在尝试从Table with expandable rows实现，但我得到了以下错误：There can only be one default row without a when predicate function.这个错误来自于这样一个事实，即我有两个<tr mat-row ...，两者都没有when谓词(...

问Angular6 Material6错误：“只能有一个默认行，而没有一个There谓词函数。”
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问Angular6 Material6错误：“只能有一个默认行，而没有一个There谓词函数。”EN