Angular - How to apply [ngStyle] conditions

Question

I have a div that I want to style based on a condition.

If styleOne is true I want a background colour of red. If StyleTwo is true, I want the background colour to be blu

Answer 1

<ion-col size="12">
  <ion-card class="box-shadow ion-text-center background-size"
  *ngIf="data != null"
  [ngStyle]="{'background-image': 'url(' + data.headerImage + ')'}">

  </ion-card>

Answer 2

[ngStyle]="{'opacity': is_mail_sent ? '0.5' : '1' }"

Answer 3

For a single style attribute, you can use the following syntax:

<div [style.background-color]="style1 ? 'red' : (style2 ? 'blue' : null)">

I assumed that the background color should not be set if neither style1 nor style2 is true.

---

Since the question title mentions ngStyle, here is the equivalent syntax with that directive:

<div [ngStyle]="{'background-color': style1 ? 'red' : (style2 ? 'blue' : null) }">

Answer 4

You can use an inline if inside your ngStyle:

[ngStyle]="styleOne?{'background-color': 'red'} : {'background-color': 'blue'}"

A batter way in my opinion is to store your background color inside a variable and then set the background-color as the variable value:

[style.background-color]="myColorVaraible"