Angular - How to apply [ngStyle] conditions

问题

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 blue. I've got half of it working with the below code.

<div id="myDiv" [ngStyle]="styleOne && {'background-color': 'red'}">

Is it possible to add a condition to say:

• if styleOne is true, do this
• if styleTwo is true, do this?

Edit

I think i've resolved it. It works. Not sure if it's the best way:

<div id="div" [ngStyle]="styleOne && {'background-color': 'red'} || styleTwo && {'background-color': 'blue'}">

回答1:

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) }">

回答2:

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"

回答3:

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

来源：https://stackoverflow.com/questions/49280975/angular-how-to-apply-ngstyle-conditions