Skip to main content

Angular 2+: ng-content

Have you ever felt the need of writing a component like the following

<my-component>
  <div> Some text here </div>
  <div> Some text here </div>
  <div> Some text here </div>
  <div> Some text here </div>
</my-component>
Now your intention here is to have your custom component and keep having the additional html that you have written between statring and ending tags. If yes, then you are on the right place.

Angular provides an element called ng-content which can used to write configurable components. This is called Component Projection, neaning the content that will be procvided inside the opening and closing brackets will be projected. It will be rendered inside a <ng-content> element. It means that you must include a <ng-content> tag somewhere in your components html template so that the provided content can be projected inside it.

So your my-component should have a template like the following

// myComponent.component.html


<div class="row">
   This is a row
   <ng-content></ng-content>
</div>

The ng-content inside above tempalte will be replaced with the provided html between <my-component> and </my-component>

I solved a very complex using this component. If you are inerested in kowing what I did, please check out my following post.

Comments

Post a Comment

Popular posts from this blog

Html5 Canvas Drawing -- Draw dotted or dashed line

This post is for those who want to use html5 canvas for drawing. The canvas API now has built in methods to create lines with dashes. The method is called setLineDash. Following is the code sample to create dashed line. var canvas = document . getElementById ( "canvas" ); var ctx = canvas . getContext ( "2d" ); ctx . setLineDash ([ 5 , 3 ]); /*Dash width and spaces between dashes.*/ ctx . beginPath (); ctx . moveTo ( 0 , 100 ); ctx . lineTo ( 400 , 100 ); ctx . stroke (); If you want to draw lines having a custom style there is no methos in the API. But fortunately there is a way to achieve this. Following is a description about how I achieved this. You can set the stroke pattern on canvas context. Stroke pattern can be created using any image. You create image for your custom pattern and set strokeStyle of the context like the following: var linePattern; imageToUsedAsPattern.onload = function() { linePattern = context.createPattern(imageToU
Post a Comment
Read more

Angular2+: ng-template

This is an angular element which is used to render HTML, it never gets displayed directly. It is used by structural directives like ngIf and ngFor. We can use them directly in some cases e.g when we want to reuse a template multiple times in our code. Suppose we have following code <ng-template> <p> Hello World! </p> </ng-template>  When it will run the code inside it will not get displayed. If you will inpect the HTML in your developer console you will see that the above will get replaced by a comment and you will find only following in its place. <!----> Now this doesn't make sense that angular is giving a component which just eats up your code and does nothing. This component is actually used to create a reusable template which can be accessd via a tempalte reference. It is used internally by angular to replace the structure directives with it and later at run time is converted into a comment. So for example if you have an ngFor in
Post a Comment
Read more

Difference between ng-template, ng-content and ng-container

While working on a very complex feature for a client in which I had to present hierarchical dynamic data in three column layout with ability to expand like google image search on each level, I came across ng-content, which seemed like a perfect fit for the solution I was thinking about implementing. But I got confused between ng-content and ng-container when I saw the generated html while debugging my code in developer console. I further investigated both ng-content and ng-container and decided to write my finding here in my blog for future references. If you are also wondering what are they for, read on. <ng-container> When you have to write different host elements to combine many structural component like the following <div *ngIf="condition"> <div *ngFor="..."> Some content here </div> </div> You get many unintentional host elements which are not required for your layout. It becomes a prolem when you have complex appl
Post a Comment
Read more