如何从指令添加/删除类 [英] How to add/remove class from directive
本文介绍了如何从指令添加/删除类的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
使用自定义指令如何根据特定条件在主机元素上添加/删除类?
Using a custom directive how would you add/remove a class on the host element based on a specific conditions?
示例:
@Directive({
selector: '[customDirective]'
})
export class CustomDirective {
constructor(service: SomService) {
// code to add class
if (service.someCondition()) {
// code to remove class
}
}
}
推荐答案
如果您不想使用ngClass
指令(提示:如果要在[ngClass]="myClasses()"
中进行杂乱的内联,则可以将函数传递给[ngClass]="myClasses()"
您的模板),您只需利用Renderer2
为其添加一个或多个类:
If you don't want to use the ngClass
directive (Hint: you can pass a function to [ngClass]="myClasses()"
if it would be to messy inline in your template) you can just utilize the Renderer2
for it to add one or more classes:
export class CustomDirective {
constructor(private renderer: Renderer2,
private elementRef: ElementRef,
service: SomService) {
}
addClass(className: string, element: any) {
this.renderer.addClass(element, className);
// or use the host element directly
// this.renderer.addClass(this.elementRef.nativeElement, className);
}
removeClass(className: string, element: any) {
this.renderer.removeClass(element, className);
}
}
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