捕获输入字段上的选项卡时不显示错误消息

Question

我有一个输入：文本字段，其中应用了一些验证规则，即required，ng-maxlength。我已经创建了一个指令来捕获该输入字段上的TAB键。问题是单击TAB和Backspace，错误消息未隐藏和显示。这是jsfiddle：http://jsfiddle.net/36qp9ekL/199/

.directive('allowTab', function () {
    return {
        require: 'ngModel',
        link: function (scope, ele, attrs, c) {
            ele.bind('keydown keyup', function (e) {                
                if(e.keyCode === 9 && e.type == 'keydown'){
                    // get caret position/selection
                    var val = this.value,
                        start = this.selectionStart,
                        end = this.selectionEnd;

                    // set textarea value to: text before caret + tab + text after caret
                    this.value = val.substring(0, start) + '[TAB]' + val.substring(end);

                    // put caret at right position again
                    this.selectionStart = this.selectionEnd = start + 5;
                    scope.$digest();
                    e.preventDefault();
                    return false;
                }
                if(e.keyCode === 8 && e.type == 'keydown'){   //on backspace remove the [Tab]
                    var val = this.value;
                    var i = this.selectionEnd;
                    if(i > 4) {
                        var prev = val.substring(i-5,i);
                        if(prev == '[TAB]') {
                            this.value = val.substring(0, i-5)+ val.substring(i);                            
                            scope.$digest();
                            e.preventDefault();
                        }
                    }
                }
            });
        }
    }

步骤：

1) Enter 'a'
2) Remove 'a' by pressing backspace
error will appear
3) Now click TAB
issue: error is not removed

Answer 1

尝试手动更改时设置视图值：

c.$setViewValue(this.value);

请参阅此fiddle。