角度 2 将位置更改为固定在滚动上 [英] angular 2 change position to fixed on scroll

问题描述

我有一个位置固定的左侧边栏.我想要实现的是，当我滚动大约 50 或 60 像素时，左侧边栏的位置应更改为固定.

Left-sidebar.component.ts

import { Component } from '@angular/core';@成分({模块 ID:module.id，选择器:'左侧边栏'，templateUrl: 'left-sidebar.html',styleUrls: ['left-sidebar.scss']})导出类 LeftSideBarComponent {}

left-sidebar.html

css

.left-nav {位置:绝对；背景:#424242；高度:100%；溢出:自动；填充:0；z-索引:1；}

如何在滚动时将左侧边栏的位置从绝对位置更改为固定位置?

解决方案

我建议你像这样使用 @HostListner 装饰器来监听滚动事件:

 import { Inject, HostListener } from "@angular/core";从@angular/platform-b​​rowser"导入{文档}；@成分({模块 ID:module.id，选择器:'左侧边栏'，templateUrl: 'left-sidebar.html',styleUrls: ['left-sidebar.scss']})导出类 LeftSideBarComponent {公共固定:boolean = false;构造函数(@Inject(DOCUMENT)私有文档:文档){}@HostListener("window:scroll", [])onWindowScroll() {让 num = this.doc.body.scrollTop;如果(数量> 50){this.fixed = true;}else if (this.fixed && num <5) {this.fixed = false;}}

将 .fixed css 添加到您的 scss 文件中，然后在您的模板中执行以下操作:

I have a left sidebar with position fixed. what I want to achieve is that when I scroll like about 50 or 60 pixel the position of the left sidebar should be changed to fixed.

Left-sidebar.component.ts

import { Component } from '@angular/core';

@Component({
  moduleId: module.id,
  selector: 'left-sidebar',
  templateUrl: 'left-sidebar.html',
  styleUrls: ['left-sidebar.scss']
})
export class LeftSideBarComponent {
}

left-sidebar.html

<div class="col-sm-2 left-nav">

</div>

css

.left-nav {
  position: absolute;
  background: #424242;
  height: 100%;
  overflow: auto;
  padding: 0;
  z-index: 1;
}

How to change position of left sidebar from absolute to fixed on scroll?

解决方案

I suggest you make use of the @HostListner decorator to listen to the scroll event just like this:

 import { Inject, HostListener } from "@angular/core";
 import { DOCUMENT } from "@angular/platform-browser";

     @Component({
         moduleId: module.id,
         selector: 'left-sidebar',
         templateUrl: 'left-sidebar.html',
         styleUrls: ['left-sidebar.scss']
     })

  export class LeftSideBarComponent {
         public fixed: boolean = false; 

         constructor(@Inject(DOCUMENT) private doc: Document) {}

         @HostListener("window:scroll", [])
         onWindowScroll() {
            let num = this.doc.body.scrollTop;
            if ( num > 50 ) {
                this.fixed = true;
            }else if (this.fixed && num < 5) {
                this.fixed = false;
            }
         }

add the .fixed css to your scss file then in your template, you do the following:

<div class="col-sm-2 left-nav" [class.fixed]="fixed">

</div>

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