// Summary://     Defines members that data entity classes can implement to provide custom,//     asynchronous validation support.    public interface INotifyDataErrorInfo    {// Summary://     Gets a value that indicates whether the object has validation errors.//// Returns://     true if the object currently has validation errors; otherwise, false.        bool HasErrors { get; }

// Summary://     Occurs when the validation errors have changed for a property or for the//     entire object.        event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged;

// Summary://     Gets the validation errors for a specified property or for the entire object.//// Parameters://   propertyName://     The name of the property to retrieve validation errors for, or null or System.String.Empty//     to retrieve errors for the entire object.//// Returns://     The validation errors for the property or object.        IEnumerable GetErrors(string propertyName);    }

    public class Student : INotifyPropertyChanged,INotifyDataErrorInfo    {//存放错误信息，一个Property可能对应多个错误信息        private Dictionary<string, List<string>> errors = new Dictionary<string, List<string>>();

        //实现INotifyPropertyChanged        public event PropertyChangedEventHandler PropertyChanged;

public void OnPropertyChanged(PropertyChangedEventArgs e)        {if (PropertyChanged != null)            {                PropertyChanged(this, e);            }        }

        //实现INotifyDataErrorInfo        public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged;

public IEnumerable GetErrors(string propertyName)        {if (string.IsNullOrEmpty(propertyName))            {return null;            }else            {if (errors.ContainsKey(propertyName))                {return errors[propertyName];                }            }return null;        }

public bool HasErrors        {get            {return (errors.Count > 0);            }        }

private void SetErrors(string propertyName, List<string> propertyErrors)        {            errors.Remove(propertyName);            errors.Add(propertyName, propertyErrors);if (ErrorsChanged != null)            {                ErrorsChanged(this, new DataErrorsChangedEventArgs(propertyName));            }        }

private void ClearErrors(string propertyName)        {            errors.Remove(propertyName);if (ErrorsChanged != null)            {                ErrorsChanged(this, new DataErrorsChangedEventArgs(propertyName));            }        }

private string name;private int age;

public String Name        {get            {return name;            }set            {                name = value;                List<string> errors = new List<string>();bool valid = true;

//数据校验                  if (name.Trim().Contains(" "))                {                    errors.Add("姓名中不能包含空格");                    valid = false;                }if (name.Length < 2 || name.Length > 4)                {                    errors.Add("姓名的长度不能低于2高于4");                    valid = false;                }

if (!valid)                {                    SetErrors("Name", errors);                }else                {                    ClearErrors("Name");                }            }        }

public int Age        {get            {return age;            }set            {                age = value;if (age < 0 || age > 150)                {                    List<string> errors = new List<string>();                    errors.Add("年龄不能小于0或大于150");                    SetErrors("Age", errors);                }else                {                    ClearErrors("Age");                }            }        }    }

<Grid x:Name="LayoutRoot" Background="White" BindingValidationError="LayoutRoot_BindingValidationError">        <Grid.RowDefinitions>            <RowDefinition Height="40"></RowDefinition>            <RowDefinition Height="40"></RowDefinition>            <RowDefinition Height="40"></RowDefinition>            <RowDefinition Height="Auto"></RowDefinition>        </Grid.RowDefinitions>        <Grid.ColumnDefinitions>            <ColumnDefinition></ColumnDefinition>            <ColumnDefinition></ColumnDefinition>        </Grid.ColumnDefinitions>        <TextBlock Text="姓名：" HorizontalAlignment="Right" VerticalAlignment="Center"></TextBlock>        <TextBox x:Name="txtName" Text="{Binding Name, Mode=TwoWay, ValidatesOnExceptions=True,             ValidatesOnNotifyDataErrors=True, NotifyOnValidationError=True}" Width="150" Grid.Column="1" HorizontalAlignment="Left" VerticalAlignment="Center">        </TextBox>        <TextBlock Text="年龄：" HorizontalAlignment="Right" Grid.Row="1" VerticalAlignment="Center"></TextBlock>        <TextBox x:Name="txtAge" Text="{Binding Age, Mode=TwoWay, ValidatesOnExceptions=True,             ValidatesOnNotifyDataErrors=True, NotifyOnValidationError=True}" Width="150" Grid.Column="1" Grid.Row="1" HorizontalAlignment="Left" VerticalAlignment="Center">        </TextBox>        <Button x:Name="Submit" Content="Submit The Data" HorizontalAlignment="Left" Grid.Row="2" Grid.Column="1" Click="Submit_Click" VerticalAlignment="Center"></Button>        <TextBlock x:Name="Summary" Text="无任何错误信息" VerticalAlignment="Center" Grid.Column="1" Grid.Row="3"></TextBlock>    </Grid>

        public MainPage()        {            InitializeComponent();

            Student product = new Student();            LayoutRoot.DataContext = product;        }

private void LayoutRoot_BindingValidationError(object sender, ValidationErrorEventArgs e)        {//可能没有Exception,但是存在错误信息            if (e.Error.Exception != null)            {//异常处理代码            }else            {                Summary.Text = e.Error.ErrorContent.ToString();                txtName.Focus();            }        }