在WPF中使用数据绑定，如果用户输入和绑定类型转换失败，控件就会显示出现错误的模板，
比如一个Textbox绑定到一个int 属性，如果用户输入一个string，那这个textbox就会显示错误模板，一般会是在TextBox外显示红线，
当然这个模板也可以自己设置。那如果这个界面有一个确定Button，我想实现TextBox里输入非数字和数字值小于0时Button都不可用，
那该怎么实现呢？
namespace WpfApplication6
{ /// <summary> /// MainWindow.xaml 的交互逻辑 /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); this.DataContext = new ViewModel(this); } } public class ViewModel : INotifyPropertyChanged { private Window win = null; private int errors = 0; private int num1 = 0; public int Num1 { get { return num1; } set { num1 = value; if (num1 < 0) { throw new ArgumentException("值太小！"); } } } private int num2 = 0; public int Num2 { get { return num2; } set { num2 = value; if (num2 > 0) { throw new ArgumentException("值太大！"); } } } public ICommand OK_Command { get { return new ReLayCommand(() => { },()=> { return errors == 0; }); } } public event PropertyChangedEventHandler PropertyChanged; private void OnRaisePropertyChanged(string name) { if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(name)); } } public ViewModel(Window win) { this.win = win; Validation.AddErrorHandler(win, ErrorHandler); } private void ErrorHandler(object sender, ValidationErrorEventArgs e) { if (e.Action == ValidationErrorEventAction.Added) { errors += 1; } if (e.Action == ValidationErrorEventAction.Removed) { errors -= 1; } OnRaisePropertyChanged("OK_Command"); } } public class ReLayCommand : ICommand { private Action _execute = null; private Func<bool> _canExecute = null; public event EventHandler CanExecuteChanged; public ReLayCommand(Action _execute, Func<bool> _canExecute = null) { this._execute = _execute; this._canExecute = _canExecute; } public bool CanExecute(object parameter) { if (_canExecute != null) return _canExecute(); return true; } public void Execute(object parameter) { if (_execute != null) _execute(); } }}<Window x:Class="WpfApplication6.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:local="clr-namespace:WpfApplication6" mc:Ignorable="d" Title="MainWindow" Height="350" Width="525"> <Window.Resources> <Style TargetType="TextBox"> <Style.Triggers> <Trigger Property="Validation.HasError" Value="true"> <Setter Property="ToolTip" Value="{Binding RelativeSource={x:Static RelativeSource.Self},Path=(Validation.Errors)[0].ErrorContent}"/> </Trigger> </Style.Triggers> </Style> </Window.Resources> <Grid> <TextBox x:Name="textBox" HorizontalAlignment="Left" Height="23" Margin="140,76,0,0" TextWrapping="Wrap" Text="{Binding Path=Num1,UpdateSourceTrigger=PropertyChanged,NotifyOnValidationError=True,ValidatesOnExceptions=True}" VerticalAlignment="Top" Width="120"/> <TextBox x:Name="textBox1" HorizontalAlignment="Left" Height="23" Margin="140,160,0,0" TextWrapping="Wrap" Text="{Binding Path=Num2,UpdateSourceTrigger=PropertyChanged,NotifyOnValidationError=True,ValidatesOnExceptions=True}" VerticalAlignment="Top" Width="120"/> <Button x:Name="button" Command="{Binding Path=OK_Command}" Content="Button" HorizontalAlignment="Left" Margin="129,239,0,0" VerticalAlignment="Top" Width="75"/> </Grid></Window>