【WPF】验证

 <Window.Resources>

        <!--数据源-->

        <local:Person Age="100" Name="Tom" x:Key="Data"></local:Person>

        <!--TextBox模板-->

        <Style  TargetType="{x:Type TextBox}">

            <Style.Triggers>

                <!--验证触发-->

                <Trigger Property="Validation.HasError" Value="True">

                    <!--错误信息模板-->

                    <Setter Property="Validation.ErrorTemplate">

                        <Setter.Value>

                            <ControlTemplate>

                                <DockPanel LastChildFill="True">

                                    <Border Background="Red" DockPanel.Dock="Right" Margin="5,0,0,0"

                                            Width="20" Height="20" CornerRadius="20"

                                            ToolTip="{Binding ElementName=customAdorner,Path=AdornedElement.(Validation.Errors)[0].ErrorContent}">

                                        <TextBlock Text="*" VerticalAlignment="Center" HorizontalAlignment="Center"

                                                   FontWeight="Bold" Foreground="White"/>

                                    </Border>

                                    <!--占位，表示修饰控件相对于ControlTemplate中其它元素所放置的位置（这个示例中用于文本框的占位）-->

                                    <AdornedElementPlaceholder Name="customAdorner" VerticalAlignment="Center">

                                        <Border BorderBrush="Red" BorderThickness="1"></Border>

                                    </AdornedElementPlaceholder>

                                </DockPanel>

                              

                            </ControlTemplate>

                        </Setter.Value>

                    </Setter>

                </Trigger>

            </Style.Triggers>

        </Style>

    </Window.Resources>

    <Grid>

        <TextBox Height="35" Width="120"

                 Text="{Binding Source={StaticResource Data},Path=Age,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged,

            ValidatesOnDataErrors=True,ValidatesOnExceptions=True,

            NotifyOnValidationError=True}" />

    </Grid>

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.ComponentModel.DataAnnotations;

using System.Linq;

using System.Text;



namespace WpfCommand.Models

{

    public class Person:INotifyPropertyChanged,IDataErrorInfo

    {



        private string _name;

        public string Name

        {

            get { return _name; }

            set {

                _name = value;

                RaisePropertyChanged("Name");

            }

        }

     private int _age;

       // [Range]  ValidationAttribute：（需要添加 System.ComponentModel.DataAnnotations.dll）
        
       [Range(19,99,ErrorMessage="未成年")]

        public int Age

        {

            get { return _age; }

            set {

                _age = value;

                RaisePropertyChanged("Age");

            }

        }



        public string Error { get { return ""; } }



        //索引器

        public string this[string ColumnName]

        {

            get {

                var vc = new ValidationContext(this, null, null);

                vc.MemberName = ColumnName;

                var res = new List<ValidationResult>();

                var result = Validator.TryValidateProperty(this.GetType().GetProperty(ColumnName).GetValue(this, null), vc, res);

                if (res.Count > 0)

                { 

                    return string.Join(Environment.NewLine,res.Select(r=>r.ErrorMessage).ToArray());

                }

                return string.Empty;

            }

            

        }



        public event PropertyChangedEventHandler PropertyChanged;



        public virtual void RaisePropertyChanged(string propertyName)

        {

            if (PropertyChanged != null)

            {

                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));

            }

            

        }

    }

}