WPF 数据验证和显示错误消息 IDataErrorInfo 和错误模板 [英] WPF data validation and display error message IDataErrorInfo and error templates

问题描述

如何使用 IDataErrorInfo 和错误模板对错误进行 WPF 数据验证并显示错误消息

How to do WPF data validation for error and display error message using IDataErrorInfo and error templates

推荐答案

ViewModel: IDataViewModel.cs

ViewModel: IDataViewModel.cs

using GalaSoft.MvvmLight;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace IDataErrorInfo_InputValidation.ViewModel
{
    class IDataViewModel:ViewModelBase,IDataErrorInfo
    {
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int  Age { get; set; }

        public string Error
        {
            get { throw new NotImplementedException(); }
        }

        public string this[string columnName]
        {
            get 
            {
                string result = null;
                if (columnName == "FirstName")
                {
                    if (string.IsNullOrEmpty(FirstName))
                        result = "Please Enter Your FirstName";
                }
                if(columnName == "LastName")
                {
                    if (string.IsNullOrEmpty(LastName))
                        result = "Please Enter Your LastName";
                }
                if(columnName == "Age")
                {
                    if(Age <= 0 || Age >= 99)
                    result ="Please Enter Valid Age";
                }

                return result;
            }
        }
    }
}

xaml : IDataView.xaml

xaml : IDataView.xaml

<Window x:Class="IDataErrorInfo_InputValidation.View.IDataView"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="IDataView" Height="300" Width="300">
    <Window.Resources>
        <!-- Error template for changing behaviour -->
        <ControlTemplate x:Key="ErrorTemplate">
            <DockPanel LastChildFill="True">
                <Border BorderBrush="Red" BorderThickness="1">
                    <AdornedElementPlaceholder />
                </Border>
            </DockPanel>
        </ControlTemplate>
        <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 HorizontalAlignment="Center">
        <Grid.RowDefinitions>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>
            <RowDefinition Height="Auto"/>            
        </Grid.RowDefinitions>
        <TextBox Text="{Binding FirstName,Mode=TwoWay,ValidatesOnDataErrors=True,NotifyOnValidationError=True,ValidatesOnExceptions=True}" Height="20"  Width="100" Margin="10"/>
        <TextBox Text="{Binding LastName,Mode=TwoWay,ValidatesOnDataErrors=True,NotifyOnValidationError=True,ValidatesOnExceptions=True}" Grid.Row="1" Height="20"  Width="100" Margin="10" />
        <TextBox Grid.Row="2" Text="{Binding Age,Mode=TwoWay,ValidatesOnDataErrors=True,NotifyOnValidationError=True,ValidatesOnExceptions=True}" Height="20" Width="100" Margin="10"/>
        <!--<TextBox Grid.Row="2" Height="20"  Width="100" Margin="10"/>-->
        <TextBox Grid.Row="3" Height="20"  Width="100" Margin="10"/>
    </Grid>
</Window>

IDataViewXaml.cs

IDataViewXaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

namespace IDataErrorInfo_InputValidation.View
{
    /// <summary>
    /// Interaction logic for IDataView.xaml
    /// </summary>
    public partial class IDataView : Window
    {
        public IDataView()
        {
            InitializeComponent();
            DataContext = new ViewModel.IDataViewModel();
        }
    }
}

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