如何使用窗体控件检查角6中文本框的负值

Question

component.ts

 this.companySettingsForm = this.formBuilder.group({
    'delivary_charge': ['', Validators.compose([Validators.required, ])],  
     });
     this.delivary_charge = this.companySettingsForm.controls['delivary_charge'];
  }

在Component.html中，我添加了min和max值，但是它不能工作

component.html

<input pInputText #value type="number" [formControl]="surcharge" min="1" 
max="9999999999999" class="input-width">

Answer 1

可以在窗体控件中使用Validators.minLength()和Validators.maxLength()设置窗体控件的最小和最大长度。

要检查负值，可以使用Validators.min()

this.companySettingsForm = this.formBuilder.group({
    'delivary_charge': ['', Validators.compose([Validators.required, Validators.minLength(3), Validators.maxLength(10), Validators.min(0)])],  
 });

Answer 2

您还可以像下面这样限制/检查component.ts中的负值

myControl:FormControl = new FormControl();
this.myControl.valueChanges.subscribe(val=>{
  if(val<0){
    // you can check negative values here and do whatever you'd like
    // you can also set the value of your input to null or 0 to prevent negative values 
    // this.myControl.setValue(null);
  }
 });