Min and max value of input in angular4 application

问题:

I have an angular4 application with a form. In this one I have an input to enter a percentage. So, I want to block the input with value between 0 and 100. I tried to add min="0" and max="100" but I can yet enter an number higher than 100 or smaller than 0.

template

<md-input-container>
  <input type="number" 
    maxlength="3" 
    min="0" 
    max="100" 
    required 
    mdInput 
    placeholder="Charge" 
    [(ngModel)]="rateInput" 
    name="rateInput">
  <md-error>Required field</md-error>
</md-input-container>

Do you know how I can do this ?

回答1:

I succeeded by using a form control. This is my html code :

    <md-input-container>
        <input type="number" min="0" max="100" required mdInput placeholder="Charge" [(ngModel)]="rateInput" name="rateInput" [formControl]="rateControl">
        <md-error>Please enter a value between 0 and 100</md-error>
    </md-input-container>

And in my typescript code, I have :

        this.rateControl = new FormControl("", [Validators.max(100), Validators.min(0)])

So, if we enter a value higher than 100 or smaller than 0, the material design input become red and the field is not validate. So after, if the value is not good, I don't save when I click on the save button.

回答2:

Actually when you use type="number" your input control populate with up/down arrow to increment/decrement numeric value, so when you update textbox value with those button it will not pass limit of 100, but when you manually give input like 120/130 and so on, it will not validate for max limit, so you have to validate it by code.

You can disable manual input OR you have to write some code on valueChange/textChange/key* event.

回答3:

Here is the solution :

This is kind of hack , but it will work

<input type="number" 
placeholder="Charge" 
[(ngModel)]="rateInput" 
name="rateInput"
pattern="^$|^([0-9]|[1-9][0-9]|[1][0][0])?"
required 
#rateInput2 = "ngModel">

<div *ngIf="rateInput2.errors && (rateInput2.dirty || rateInput2.touched)"
    <div [hidden]="!rateInput2.errors.pattern">
        Number should be between 0 and 100
    </div>
</div>

Here is the link to the plunker , please have a look.

回答4:

If you are looking to validate length use minLength and maxLength instead.