CommandBinding问题.如何启用命令按钮 [英] CommandBinding question. How to enable command button

问题描述

我的代码在这里>>

public class Player:INotifyPropertyChanging
{
        string addressBar;
        public string Url
        {
            get {

                return addressBar;
            }
            set { addressBar = value; OnPropertyChanged("Url"); }
        }
        public Regex regVillage = new Regex(@"\?doc=\d+&sys=[a-zA-Z0-9]{2}");

        RelayCommand _AddAttackTask;
        public ICommand AddAttackTask
        {
            get {
                if (_AddAttackTask == null)
                {
                    _AddAttackTask = new RelayCommand(param =>
                    {

                    }, param => this.CanAttack);
                }
                return _AddAttackTask;
            }
        }

        public Boolean CanAttack
        {
            get{
                if (Url == null) return false;
                return regVillage.IsMatch(Url);
            }            
        }
}

在xaml上，我有文本框和按钮.文本框由 url 绑定，按钮由 AddAttackTask 绑定.当我更改文本框值时，网址已更改.主要目标是在更改网址时，启用或禁用按钮.但是按钮始终处于禁用状态.

On the xaml, i have textbox and button. Textbox binded by url, button binded by AddAttackTask. When i change textbox value,Url changed.Main target is When changing url, button bring to enable or disable. But button always disabled.

我正在从

I'm getting RelayCommand class from WPF Apps With The Model-View-ViewModel Design Pattern

我的代码有什么问题?

请修复我的命令绑定！

推荐答案

我自己找到了它.

更改属性后，必须调用 CommandManager.InvalidateRequerySuggested(); 函数

Must call CommandManager.InvalidateRequerySuggested(); function after changing property

public string Url
        {
            get {

                return addressBar;
            }
            set { addressBar = value; OnPropertyChanged("Url"); 
                  CommandManager.InvalidateRequerySuggested();
            }
        }

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