WPF开发随笔收录-DataAnnotations实现数据校验（MVVM架构下）
一、前言
在自己的项目中挺多地方需要涉及到数据验证的，初期的实现方式都是通过点击确定后再逐个验证数据是否符合要求，但这种方式会让后台代码变得很多很乱。于是就开始在网上需求好的解决方式，刚好看到了一个大佬的博客写了关于数据验证的博客，也成功将那个方法用在项目中了，今天就来这里分享一下。博客原文：https://www.cnblogs.com/wzh2010/p/6518834.html
二、正文
1、这里写一个简单的例子来作为参考，首先新建个项目，按照常规MVVM构建好项目，如下图。然后添加需要用到的通知基类和命令基类
2、然后就是添加一个验证的基类ValidateModelBase，后面需要实现验证的类直接继承这个类即可，这个代码是直接搬大佬的
public class ValidateModelBase : NotifyBase, IDataErrorInfo { public ValidateModelBase() { } #region 属性 /// <summary> /// 表当验证错误集合 /// </summary> public Dictionary<string, string> dataErrors = new Dictionary<string, string>(); /// <summary> /// 是否验证通过 /// </summary> public bool IsValidated { get { if (dataErrors != null && dataErrors.Count > 0) { return false; } return true; } } #endregion public string this[string columnName] { get { ValidationContext 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) { string errorInfo = string.Join(Environment.NewLine, res.Select(r => r.ErrorMessage).ToArray()); AddDic(dataErrors, columnName, errorInfo); return errorInfo; } RemoveDic(dataErrors, columnName); return null; } } public string Error { get { return null; } } #region 附属方法 /// <summary> /// 移除字典 /// </summary> /// <param name="dics"></param> /// <param name="dicKey"></param> private void RemoveDic(Dictionary<string, string> dics, string dicKey) { dics.Remove(dicKey); } /// <summary> /// 添加字典 /// </summary> /// <param name="dics"></param> /// <param name="dicKey"></param> private void AddDic(Dictionary<string, string> dics, string dicKey, string dicValue) { if (!dics.ContainsKey(dicKey)) dics.Add(dicKey, dicValue); } #endregion }
3、接着我们创建一个类，并添加需要验证的字段
public class UserModel : ValidateModelBase { private string userName; [Required(ErrorMessage = "用户名不可为空")] public string UserName { get { return userName; } set { userName = value; DoNotify(); } } private string userAge; [Required(ErrorMessage = "年龄不可为空")] [Range(0, 100, ErrorMessage = "年龄范围为0~100")] public string UserAge { get { return userAge; } set { userAge = value; DoNotify(); } } private bool isFormValid; public bool IsFormValid { get { return isFormValid; } set { isFormValid = value; DoNotify(); } } }
4、重写一下TextBox的Validation.ErrorTemplate模板
<Style x:Key="{x:Type TextBoxBase}" BasedOn="{x:Null}" TargetType="{x:Type TextBoxBase}"> <Setter Property="BorderThickness" Value="1" /> <Setter Property="Padding" Value="2,1,1,1" /> <Setter Property="AllowDrop" Value="true" /> <Setter Property="FocusVisualStyle" Value="{x:Null}" /> <Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst" /> <Setter Property="Stylus.IsFlicksEnabled" Value="False" /> <Setter Property="SelectionBrush" Value="{DynamicResource Accent}" /> <Setter Property="Validation.ErrorTemplate"> <Setter.Value> <ControlTemplate> <StackPanel Orientation="Vertical"> <Border x:Name="adornerborder" BorderThickness="1"> <Grid> <AdornedElementPlaceholder x:Name="adorner" Margin="-1" /> </Grid> </Border> <Border x:Name="errorBorder" Background="Transparent" CornerRadius="0" IsHitTestVisible="False" Opacity="0"> <TextBlock VerticalAlignment="Center" Foreground="Red" Text="{Binding ElementName=adorner, Path=AdornedElement.(Validation.Errors)[0].ErrorContent}"/> </Border> </StackPanel> <ControlTemplate.Triggers> <DataTrigger Value="True"> <DataTrigger.Binding> <Binding ElementName="adorner" Path="AdornedElement.Tag" /> </DataTrigger.Binding> <DataTrigger.EnterActions> <BeginStoryboard x:Name="fadeInStoryboard1"> <Storyboard> <DoubleAnimation Storyboard.TargetName="errorBorder" Storyboard.TargetProperty="Opacity" To="1" Duration="00:00:00.15" /> </Storyboard> </BeginStoryboard> </DataTrigger.EnterActions> <DataTrigger.Setters> <Setter TargetName="adornerborder" Property="BorderBrush" Value="#FFdc000c" /> </DataTrigger.Setters> </DataTrigger> <DataTrigger Value="True"> <DataTrigger.Binding> <Binding ElementName="adorner" Path="AdornedElement.IsKeyboardFocused" /> </DataTrigger.Binding> <DataTrigger.EnterActions> <BeginStoryboard x:Name="fadeInStoryboard"> <Storyboard> <DoubleAnimation Storyboard.TargetName="errorBorder" Storyboard.TargetProperty="Opacity" To="1" Duration="00:00:00.15" /> </Storyboard> </BeginStoryboard> </DataTrigger.EnterActions> <DataTrigger.Setters> <Setter TargetName="adornerborder" Property="BorderBrush" Value="#FFdc000c" /> </DataTrigger.Setters> </DataTrigger> </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> </Style>
5、接着在主窗口添加两个TextBox，然后绑定上对应的字段，记得要加上这个ValidatesOnDataErrors=True，不然无效
<Grid> <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center"> <StackPanel Margin="0,10" Orientation="Horizontal"> <Label Width="80" Content="用户姓名：" /> <TextBox Width="150" Tag="{Binding UserModel.IsFormValid, UpdateSourceTrigger=PropertyChanged}" Text="{Binding UserModel.UserName, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" /> </StackPanel> <StackPanel Margin="0,10" Orientation="Horizontal"> <Label Width="80" Content="用户年龄：" /> <TextBox Width="150" Tag="{Binding UserModel.IsFormValid, UpdateSourceTrigger=PropertyChanged}" Text="{Binding UserModel.UserAge, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" /> </StackPanel> <Button Margin="0,10,0,0" Command="{Binding SubmitCommand}" Content="提交" /> </StackPanel> </Grid>
6、然后就是ViewModel的代码
public class MainWindowViewModel : NotifyBase { private UserModel userModel; public UserModel UserModel { get { return userModel; } set { userModel = value; DoNotify(); } } public CommandBase SubmitCommand { get; set; } = new CommandBase(); public MainWindowViewModel() { UserModel = new UserModel(); SubmitCommand.DoExecute = new Action<object>(DoSumit); SubmitCommand.DoCanExecute = new Func<object, bool>((o) => { return true; }); } private void DoSumit(object obj) { if (UserModel.IsValidated) MessageBox.Show("验证通过！"); else { UserModel.IsFormValid = true; var dataErrors = UserModel.dataErrors; MessageBox.Show("验证失败"); } } }
7、到这里功能的实现就基本完成了，不擅长讲解原理，不太懂得可以研究研究官方文档获取其他大佬的文章，实现效果如下：
