无废话WPF系列10: Binding对数据的检验

设置Binding的ValidationRules属性对Binding进行检验

 <StackPanel>
        <TextBox x:Name="txtAge" FontSize="30" Foreground="Red"></TextBox>
        <TextBlock x:Name="errorSummary" FontSize="30" Foreground="Red"></TextBlock>

</StackPanel>

后台代码

public partial class MainWindow : Window
    {
        
        public MainWindow()
        {
            InitializeComponent();
            Person p = new Person { Age = 20, Name = "Tom" };
            Binding binding = new Binding("Age") { Source = p };

            binding.NotifyOnValidationError = true;

            binding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;
            RangeValidationRule rv = new RangeValidationRule();
            binding.ValidationRules.Add(rv);
            this.txtAge.SetBinding(TextBox.TextProperty, binding);

            this.txtAge.AddHandler(Validation.ErrorEvent, new RoutedEventHandler(this.ValidationError));
        }

        void ValidationError(object sender, RoutedEventArgs e)
        {
            if (Validation.GetErrors(this.txtAge).Count > 0)
            {
                this.txtAge.ToolTip = Validation.GetErrors(this.txtAge)[0].ErrorContent.ToString();
                this.errorSummary.Text = Validation.GetErrors(this.txtAge)[0].ErrorContent.ToString();

                // You can do everything here when validation error occurs
            }
        }
        
    }
}

同样，我们在XAML里也可以设置验证

<StackPanel>
        <TextBox x:Name="txtAge" FontSize="30" Foreground="Red"   Validation.Error="txtAge_Error">
            <Binding NotifyOnValidationError="True" Path="Age" UpdateSourceTrigger="PropertyChanged">
                <Binding.ValidationRules>
                    <local:RangeValidationRule></local:RangeValidationRule>
                </Binding.ValidationRules>
            </Binding>
        </TextBox>
        <TextBlock x:Name="errorSummary" FontSize="30" Foreground="Red"></TextBlock>
</StackPanel>

后台代码：

public partial class MainWindow : Window
    {        
        public MainWindow()
        {
            InitializeComponent();
            Person p = new Person { Age = 20, Name = "Tom" };
            this.DataContext = p;           
        }        
        private void txtAge_Error(object sender, ValidationErrorEventArgs e)
        {
            if (Validation.GetErrors(this.txtAge).Count > 0)
            {
                this.txtAge.ToolTip = Validation.GetErrors(this.txtAge)[0].ErrorContent.ToString();

                this.errorSummary.Text = Validation.GetErrors(this.txtAge)[0].ErrorContent.ToString();
                // You can do everything here when validation error occurs
            }
        }        
}