WPF 使用绑定验证实现输入验证通过后才可提交

参考

• deepseek
• 豆包
• copilot
• https://learn.microsoft.com/zh-cn/dotnet/desktop/wpf/data/how-to-implement-binding-validation
• https://learn.microsoft.com/zh-cn/dotnet/api/system.windows.controls.validation.errortemplate?view=windowsdesktop-9.0
• https://cloud.tencent.com/developer/ask/sof/111142093
• https://cloud.tencent.com/developer/ask/sof/108693498
• https://dev59.com/iFPTa4cB1Zd3GeqPhTp3
• https://stackoverflow.org.cn/questions/4635716

环境

软件/系统	版本	说明
Windows	windows 10 专业版 22H2 64 位操作系统, 基于 x64 的处理器
Microsoft Visual Studio	Community 2022 (64 位) - Current 版本 17.14.9
Prism Template Pack	2.4.1	Microsoft Visual Studio 扩展
.NET	6
Prism.Unity	8.1.97	nuget依赖库（使用 Prism Template Pack 创建项目时选择的容器，使用模板创建的项目自动安装）
MaterialDesignThemes	5.2.1	nuget依赖库

正文

步骤

1. 实现 AccountLoginValidationRule.cs
2. Login.xaml 页面附加属性类的命名空间 xmlns:validationRule="clr-namespace:WPFNetConnect.ValidationRules"
3. 在控件中使用

   <TextBox x:Name="LoginAccountTextBox" Style="{StaticResource LoginAccountTextBox}">
   	<Binding Path="Account">
   		<Binding.ValidationRules>
   			<!--  可以带参数，可以多条条件  -->
   			<!--  validationRule:AccountLoginValidationRule Min="2" /  -->
   			<!--  validationRule:AccountLoginValidationRule Min="2" Max="10" /  -->
   			<validationRule:AccountLoginValidationRule />
   		</Binding.ValidationRules>
   	</Binding>
   </TextBox>
   

4. 提交命令在创建时，也要编写 CanExecute 逻辑，否则首次初始化，绑定验证默认为True，导致提交按钮可用

主要代码

1. AccountLoginValidationRule.cs

   using System;
   using System.Collections.Generic;
   using System.Globalization;
   using System.Linq;
   using System.Security.Principal;
   using System.Text;
   using System.Threading.Tasks;
   using System.Windows.Controls;
   using System.Windows.Input;
   // https://learn.microsoft.com/zh-cn/dotnet/desktop/wpf/data/how-to-implement-binding-validation
   namespace WPFNetConnect.ValidationRules
   {
   	class AccountLoginValidationRule : ValidationRule
   	{
   		/// <summary>
   		/// 最短长度
   		/// </summary>
   		public byte Min { get; set; } = 8;
   		/// <summary>
   		/// 最大长度
   		/// </summary>
   		public byte Max { get; set; } = 16;
   
   		public override ValidationResult Validate(object value, CultureInfo cultureInfo)
   		{
   			var val = value as string;
   			if (string.IsNullOrEmpty(val))
   			{
   				return new ValidationResult(false, "请输入正确的账号");
   			}
   			if (val.Length < Min || val.Length > Max)
   			{
   				return new ValidationResult(false, "请输入正确的账号");
   			}
   			return ValidationResult.ValidResult;
   		}
   	}
   }
   
   

2. Login.xaml

   <Window
   	x:Class="WPFNetConnect.Views.Login"
   	xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
   	xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
   	xmlns:helper="clr-namespace:WPFNetConnect.Helper"
   	xmlns:prism="http://prismlibrary.com/"
   	xmlns:validationRule="clr-namespace:WPFNetConnect.ValidationRules"
   	Title="{Binding Title}"
   	Width="1280"
   	Height="800"
   	prism:ViewModelLocator.AutoWireViewModel="True"
   	WindowStartupLocation="CenterScreen">
   	<Window.Resources>
   		<ResourceDictionary>
   			<!--  单独引入外部样式  -->
   			<ResourceDictionary.MergedDictionaries>
   				<ResourceDictionary Source="/Styles/LoginStyle.xaml" />
   			</ResourceDictionary.MergedDictionaries>
   		</ResourceDictionary>
   	</Window.Resources>
   	<Grid>
   		<Grid.ColumnDefinitions>
   			<ColumnDefinition Width="512" />
   			<ColumnDefinition />
   		</Grid.ColumnDefinitions>
   		<Image Grid.Column="0" Style="{StaticResource LoginLeft}" />
   		<StackPanel Grid.Column="1" Style="{StaticResource LoginRight}">
   			<Label Style="{StaticResource LoginTitle}">欢迎回来</Label>
   			<Label Style="{StaticResource LoginDesc}">登陆到您的账户</Label>
   			<Label Style="{StaticResource LoginAccountTitle}">用户名</Label>
   			<TextBox x:Name="LoginAccountTextBox" Style="{StaticResource LoginAccountTextBox}">
   				<Binding Path="Account">
   					<Binding.ValidationRules>
   						<!--  可以带参数，可以多条条件  -->
   						<!--  validationRule:AccountLoginValidationRule Min="2" /  -->
   						<!--  validationRule:AccountLoginValidationRule Min="2" Max="10" /  -->
   						<validationRule:AccountLoginValidationRule />
   					</Binding.ValidationRules>
   				</Binding>
   			</TextBox>
   			<Label Style="{StaticResource LoginPasswordTitle}">密码</Label>
   			<PasswordBox
   				x:Name="LoginPasswordBox"
   				helper:PasswordBoxHelper.Password="{Binding Password, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
   				Style="{StaticResource LoginPasswordBox}" />
   			<Button
   				Command="{Binding SubmitBtnCommand}"
   				Content="登录"
   				Style="{StaticResource LoginSubmitButton}" />
   			<Label Style="{StaticResource LoginErrorTip}">无法登录？联系管理员</Label>
   		</StackPanel>
   		<Label
   			Grid.Column="1"
   			Content="NetConnect v1.0.5"
   			Style="{StaticResource LoginVersion}" />
   	</Grid>
   </Window>
   
   

3. LoginViewModel.cs

   using log4net;
   using Prism.Commands;
   using Prism.Mvvm;
   using System;
   using System.CodeDom.Compiler;
   using System.Diagnostics;
   using System.Windows.Controls;
   using System.Windows.Input;
   
   namespace WPFNetConnect.ViewModels
   {
   	public class LoginViewModel : BindableBase
   	{
   		private static readonly ILog _logger = LogManager.GetLogger(typeof(LoginViewModel));
   
   		private string _title = "Login";
   		public string Title
   		{
   			get { return _title; }
   			set { SetProperty(ref _title, value); }
   		}
   		private string _account = "";
   		public string Account
   		{
   			get { return _account; }
   			set { 
   				SetProperty(ref _account, value);
   				// 当账号或密码改变时，重新计算提交按钮的可执行状态
   				SubmitBtnCommand?.RaiseCanExecuteChanged(); 
   			}
   		}
   		private string _password = "";
   		public string Password
   		{
   			get { return _password; }
   			set { 
   				SetProperty(ref _password, value);
   				// 当账号或密码改变时，重新计算提交按钮的可执行状态
   				SubmitBtnCommand?.RaiseCanExecuteChanged(); 
   			}
   		}
   		/// <summary>
   		/// 点击登录按钮的命令
   		/// </summary>
   		public DelegateCommand SubmitBtnCommand { get; set; }
   
   		/// <summary>
   		/// 是否可以提交  
   		/// </summary>
   		/// <returns></returns>
   		public bool SubmitBtnCommandCanExecute()
   		{
   			return !string.IsNullOrEmpty(Account) && !string.IsNullOrEmpty(Password);
   		}
   
   		/// <summary>
   		/// 点击登录按钮的执行方法
   		/// </summary>
   		public void SubmitBtnCommandExecute()
   		{
   			_logger.Info("点击登录");
   			Debug.WriteLine(Account);
   			Debug.WriteLine(Password);
   			if ("admin".Equals(Account) && "123456".Equals(Password))
   			{
   				System.Windows.MessageBox.Show("登录成功");   
   				// Application.Current.MainWindow 就是当前的主窗口
   				var loginView =  Application.Current.MainWindow;
   				// 使用Prism框架的依赖注入容器来创建主窗口
   				var mainView = Container.Resolve<MainWindow>();
   				// 重新指定主窗口
   				Application.Current.MainWindow = mainView;
   				mainView.Show();
   				loginView.Close();
   			}
   			else
   			{
   				System.Windows.MessageBox.Show("登录失败");
   			}
   		}
   
   		public LoginViewModel()
   		{
   			SubmitBtnCommand = new DelegateCommand(SubmitBtnCommandExecute, SubmitBtnCommandCanExecute);
   		}
   	}
   }