更改数据时,Angular 2 Cursor在文本框末尾跳转

@Directive({
    selector: '[validateName]',host: {
        '(ngModelChange)': 'onInputChange($event,false)','(keydown.backspace)': 'onInputChange($event.target.value,true)','(focusout)': 'removeClass()'
    }
})

export class NameValidator {

    constructor(public model: NgControl,public renderer: Renderer,public el: ElementRef) { }

    onInputChange(event,backspace) {
        if (!backspace) {
            // Remove invalid characters (keep only valid characters)
            var newVal = event.replace(/^[0-9s]/g,'').replace(/[^A-Za-z0-9_$]/g,'');

            // Add class for invalid name. 
            if (/^[0-9s]/g.test(event) || /[^A-Za-z0-9_$]/g.test(event)) {
                this.renderer.setElementClass(this.el.nativeElement,'invalid-name',true);
            }
            else {
                this.renderer.setElementClass(this.el.nativeElement,false);
            }
            // set the new value
            this.model.valueAccessor.writeValue(newVal);
        }
    }
    removeClass() {
        this.renderer.setElementClass(this.el.nativeElement,false);
    }
}

这是因为DefaultValueAccessor盲目地写了元素值,如果有焦点或不焦点,选择与否.我必须自己处理这样的行为,因为我使用的是自动保存的表单,我不得不重写DefaultValueAccessor并创建一个只有写入值的文件(如果不同的话)(我认为这对你不起作用),见下文) ：

export const DEFAULT_VALUE_ACCESSOR: any = {
    provide: NG_VALUE_ACCESSOR,useExisting: forwardRef(() => DefaultValueAccessor),multi: true
};

@Directive({
    selector: "input:not([type=checkbox])[formControlName],textarea[formControlName],input:not([type=checkbox])[formControl],textarea[formControl],input:not([type=checkbox])[ngModel],textarea[ngModel],[ngDefaultControl]",host: {"(input)": "onChange($event.target.value)","(blur)": "onTouched()"},providers: [DEFAULT_VALUE_ACCESSOR]
})
export class DefaultValueAccessor implements ControlValueAccessor {
    onChange = (_: any) => {
    };
    onTouched = () => {
    };

    constructor(private _renderer: Renderer,private _elementRef: ElementRef) {
    }

    writeValue(value: any): void {
        const normalizedValue = value == null ? "" : value;
        // line bellow is the only line I added to the original one
        if ((this._elementRef.nativeElement as HTMLInputElement).value !== normalizedValue) 
            this._renderer.setElementProperty(this._elementRef.nativeElement,"value",normalizedValue);
    }

    registerOnChange(fn: (_: any) => void): void {
        this.onChange = fn;
    }

    registerOnTouched(fn: () => void): void {
        this.onTouched = fn;
    }

    setDisabledState(isDisabled: boolean): void {
        this._renderer.setElementProperty(this._elementRef.nativeElement,"disabled",isDisabled);
    }
}

对于您的情况,您可能需要处理输入选择：

let start=this.el.nativeElement.selectionStart;
let end = this.el.nativeElement.selectionEnd;
this.model.valueAccessor.writeValue(newVal);
this.el.nativeElement.setSelectionRange(start,end);

请注意,在修改输入时可能不准确…