Hey angular geek, if you have the Error NG8001: ‘Mat-Form-Field’ Is Not a Known Element in Angular, you are at the correct place to find the solution.
I was developing a mini project using Angular 9 at the front-end with the Angular material theme. I was a novice to the Angular at that time.
After some development, I tried to put a form field in a dialog box of an angular material theme. However, my code was not working out. The material theme was not applying to the input field I added to the dialog box. Even more, I was having an error that Mat-Form-Field is not a known element.
Error NG8001: Is Not a Known Element
The above error for any angular element occurs when we forget to import that element directives from the angular source to our working component.ts file.
However, when I tried to debug, I found that the input skin of the angular material theme was applied to the app.module.html file. And the same input field code was not working inside the dialog file.
But, I have already imported all the necessary components from the angular material directive. My code was as mentioned below.
app.module.ts
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent, GetStartedDialog } from './app.component';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
import {MatToolbarModule} from '@angular/material/toolbar';
import {MatButtonModule} from '@angular/material/button';
import {MatDialogModule} from '@angular/material/dialog';
import {MatInputModule} from '@angular/material/input';
@NgModule({
imports: [
BrowserModule,
AppRoutingModule,
BrowserAnimationsModule,
MatToolbarModule,
MatButtonModule,
MatDialogModule,
MatInputModule
],
declarations: [
AppComponent
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
As you can see, all the necessary components are already imported in the app.module.ts file.
app.component.ts
import { Component } from '@angular/core';
import {MatDialog, MatDialogRef} from '@angular/material/dialog';
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.scss']
})
export class AppComponent {
constructor(public dialog: MatDialog) {}
openDialog(): void {
const dialogRef = this.dialog.open(GetStartedDialog, {
width: '300px'
});
dialogRef.afterClosed().subscribe(result => {
console.log('The dialog was closed');
});
}
}
@Component({
selector: 'get-started-dialog',
templateUrl: 'get-started-dialog.html',
})
export class GetStartedDialog {
constructor(
public dialogRef: MatDialogRef) {}
onNoClick(): void {
this.dialogRef.close();
}
}
app.component.ts
<section class="mat-typography">
<div>
<button mat-raised-button color="primary" (click)="openDialog()">Get Started</button>
</div>
</section>
get-started-dialog.html
<div mat-dialog-content style="text-align: center;">
<h3 class="text-accent">Dialog</h3>
<hr>
<p>Enter your details.</p>
<br>
<mat-form-field class="full-width">
<mat-label>Name</mat-label>
<input matInput placeholder="Enter Your Full Name">
</mat-form-field>
</div>
Solution
After some hours of research and debugging, I found that the angular generates dynamic content inside the dialog element.
So we have to add the dialog box class at declarations and entryComponents in the @NgModule in our module.ts file. My app.module.ts file was as follows after the change.
Updated app.module.ts
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent, GetStartedDialog } from './app.component';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
import {MatToolbarModule} from '@angular/material/toolbar';
import {MatButtonModule} from '@angular/material/button';
import {MatDialogModule} from '@angular/material/dialog';
import {MatInputModule} from '@angular/material/input';
@NgModule({
imports: [
BrowserModule,
AppRoutingModule,
BrowserAnimationsModule,
MatToolbarModule,
MatButtonModule,
MatDialogModule,
MatInputModule
],
declarations: [
AppComponent,
GetStartedDialog
],
entryComponents: [
GetStartedDialog
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
Explanation
As you can see, I added the GetStartedDialog class inside declarations and entryComponents, which helps the dialog box to compile its inside angular components/elements at the runtime.
Conclusion
I hope now you can also resolve your problem of not having a material design of an Angular element inside the dialog box.
Please comment your problem below, I will be happy to help you.
Enjoy Debugging 😀