WPF MVVMToolkit框架學習-ObservableValidator

ObservableValidator基礎模型用來驗證數據 和其他框架的基本上一樣

后台代碼

using Microsoft.Toolkit.Mvvm.ComponentModel;
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace MVVMToolkit框架學習
{
    public class NumberAttribute : ValidationAttribute
    {
        public NumberAttribute()
        {
        }

        public override string FormatErrorMessage(string name)
        {
            return base.FormatErrorMessage(name);
        }

        protected override ValidationResult? IsValid(object? value, ValidationContext validationContext)
        {
            if (value == null || string.IsNullOrWhiteSpace(value.ToString()))
            {
                return new ValidationResult("內容為空！");
            }
            if (!double.TryParse(value.ToString(), out _))
            {
                return new ValidationResult($"{value}內容不能轉換為數值！");
            }

            return ValidationResult.Success;
        }
    }

    public class ValidatorVM : ObservableValidator
    {
        private string _name;

        private string _weight;

        [Required(AllowEmptyStrings = false, ErrorMessage = "名字不可為空")]
        [MaxLength(6, ErrorMessage = "長度不能大於6")]
        public string Name
        {
            get => _name;

            //需要驗證屬性就使用重載方法
            set => SetProperty(ref _name, value, true);
        }

        [Number]
        public string Weight
        {
            get => _weight;

            //驗證自定義屬性
            set => SetProperty(ref _weight, value, true);
        }

        public ValidatorVM()
        {
        }
    }
}

前台代碼

<Window
    x:Class="MVVMToolkit框架學習.ValidateView"
    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:local="clr-namespace:MVVMToolkit框架學習"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    Title="ValidateView"
    Width="800"
    Height="450"
    d:DataContext="{d:DesignInstance Type={x:Type local:ValidatorVM}}"
    FontSize="30"
    mc:Ignorable="d">
    <Window.DataContext>
        <local:ValidatorVM />
    </Window.DataContext>
    <Window.Resources>
        <Style TargetType="TextBox">
            <Setter Property="Validation.ErrorTemplate">
                <Setter.Value>
                    <ControlTemplate>
                        <StackPanel>
                            <AdornedElementPlaceholder />
                            <ItemsControl ItemsSource="{Binding}">
                                <ItemsControl.ItemTemplate>
                                    <DataTemplate>
                                        <TextBlock
                                            Foreground="Red"
                                            Text="{Binding ErrorContent}" />
                                    </DataTemplate>
                                </ItemsControl.ItemTemplate>
                            </ItemsControl>
                        </StackPanel>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>
    <Grid>
        <StackPanel
            MinWidth="200"
            HorizontalAlignment="Center"
            VerticalAlignment="Center"
            Orientation="Vertical">
            <TextBlock Text="Name" />
            <TextBox
                Margin="0,0,0,30"
                Text="{Binding Name}" />

            <TextBlock Text="Weight" />
            <TextBox
                Margin="0,0,0,30"
                Text="{Binding Weight}" />
        </StackPanel>
    </Grid>
</Window>