WPF --- TextBox的输入校验
引言在WPF应用程序开发中，数据校验是确保用户输入数据的正确性和完整性的重要一环。
之前在做一些参数配置功能时，最是头疼各种参数校验，查阅一些资料后，我总结了数据校验方式有两种：
[*]ValidationRule
[*]IDataErrorInfo
接下来分别介绍这两种校验方式。
ValidationRule
ValidationRule 是一个抽象类，提供了抽象方法 Validate(), 它是WPF中用于数据验证的一种机制，它可以在用户输入数据之前或之后执行自定义的验证逻辑。可以轻松地实现对数据的格式、范围、逻辑等方面的验证，并在验证失败时提供相应的反馈信息。
ValidationRule主要作用域在前端页面上。
基本用法
首先创建一个 ValidationRule，我这里设定了两个属性 MaxVal、MinVal，然后在 Validate() 方法中判断空、判断大于上限或小于下限，然后在符合条件是，返回 ValidationResult，并给出错误提示：
public class IntegerValidationRule : ValidationRule
{
public int MaxVal { get; set; }
public int MinVal { get; set; }
public override ValidationResult Validate(object value, CultureInfo cultureInfo)
{
string text = value as string;
if (!int.TryParse(text, out int result))
{
return new ValidationResult(false, "Text cannot be empty.");
}
if (result > MaxVal)
{
return new ValidationResult(false, "Value out of upper limit range.");
}
if (result < MinVal)
{
return new ValidationResult(false, "Value out of lower limit range.");
}
return ValidationResult.ValidResult;
}
}接下来创建有个测试使用的 ViewModel:
public class TestViewModel : INotifyPropertyChanged
{
private TestViewModel() { }
public static TestViewModel Instance { get; } = new TestViewModel();
public event PropertyChangedEventHandler? PropertyChanged;
protected void OnPropertyChanged(string propertyName)
{
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
}
private int testField1;
/// <summary>
/// 测试属性1
/// </summary>
public int TestField1
{
get => testField1;
set
{
testField1 = value;
OnPropertyChanged(nameof(TestField1));
}
}
private int testField2;
/// <summary>
/// 测试属性2
/// </summary>
public int TestField2
{
get => testField2;
set
{
testField2 = value;
OnPropertyChanged(nameof(TestField2));
}
}
}在测试之前，我们可以先看一下 Binding 的方法列表：
可以看到 ValidationRules 是 Binding 下的集合，这意味着 ValidationRule 是在 Binding 下使用且可以执行多个校验规则。校验时按照顺序依次校验。
接下来我们创建一个WPF应用程序，在界面添加 TextBox，命名为”textbox1“,将文本绑定在 TestViewModel 的 TestField1。
且为Validation.ErrorTemplate 绑定一个模板，这里绑定了一个红色的感叹号。
然后为 TextBox 设置触发器，当 Validation.HasError为 true时，将 ToolTip 绑定校验失败的错误提示。
代码如下：
<Window
x:
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:WpfApp4"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
Title="MainWindow"
Width="900"
Height="450"
mc:Ignorable="d">
<Window.Resources>
<ControlTemplate x:Key="ValidationTemplate">
<DockPanel>
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> <TextBlock
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> Margin="-10,0,0,0"
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> VerticalAlignment="Center"
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> FontSize="22"
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> Foreground="Red"
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> Text="!" />
</DockPanel>
</ControlTemplate>
</Window.Resources>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="1*" />
<ColumnDefinition Width="1*" />
</Grid.ColumnDefinitions>
<StackPanel Grid.Column="0">
<TextBlock
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> HorizontalAlignment="Center"
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> FontSize="18"
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> FontWeight="Bold"
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> Text="Validation Demo" />
<TextBox
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> Name="textBox1"
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> Height="30"
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> Margin="10"
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> FontSize="22"
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> Validation.ErrorTemplate="{StaticResource ValidationTemplate}">
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> <TextBox.Text>
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> <Binding Path="TestField1" UpdateSourceTrigger="PropertyChanged">
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> <Binding.ValidationRules>
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel><StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel><local:IntegerValidationRule
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel><StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> MaxVal="999"
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel><StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> MinVal="5" />
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> </Binding.ValidationRules>
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> </Binding>
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> </TextBox.Text>
</TextBox>
</StackPanel>
</Grid>
</Window>最后在窗体后台绑定 ViewModel:
public MainWindow()
{
InitializeComponent();
this.DataContext =TestViewModel.Instance;
}测试
[*]为空时，出现红色叹号，ToolTip 提示 "Text cannot be empty."
[*]小于下限时，出现红色叹号，ToolTip 提示 "Value out of lower limit range."
[*]大于上限时，出现红色叹号，ToolTip 提示 "Value out of upper limit range."
IDataErrorInfo
IDataErrorInfo 是一个接口，Viewmodel 实现接口用于在后台，提供数据验证和错误信息。
IDataErrorInfo 主要作用域为后台 ViewModel
该接口包含两个成员：Error 和 this。这两个成员允许你在数据绑定时提供验证错误信息。
基本用法
接下来，在程序里添加 TextBox，命名为”textbox2“，并添加一个 TextBlock 绑定 Error 展示在界面。
<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel>后台 TestViweModel 实现 IDataErrorInfo，依旧是判断上限值和下限值，此处不判断空，是因为后台 TestField2 类型是Int，为空时不会赋值，代码如下：
public class TestViewModel : INotifyPropertyChanged, IDataErrorInfo{ //省略上文已有代码..。 private string error; public string Error { get => error; set { error = value; OnPropertyChanged(nameof(Error)); } } public string this { get { switch (columnName) {<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> case nameof(TestField2):<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> return CheckTestFild2();<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> default:<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> return null; } } } public int MaxVal = 999; public int MinVal = 5; private string CheckTestFild2() { if (TestField2 > MaxVal) { Error = "Value out of upper limit range in viewmodel."; } else if (TestField2 < MinVal) { Error = "Value out of lower limit rangein viewmodel."; } else { Error = string.Empty; }<StackPanel Grid.Column="1">
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Text="IDataErrorInfo Demo" />
<TextBox
Name="textBox2"
Margin="10"
VerticalAlignment="Center"
FontSize="22"
Text="{Binding TestField2, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />
<TextBlock
HorizontalAlignment="Center"
FontSize="18"
FontWeight="Bold"
Foreground="Red"
Text="{Binding Error, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
</StackPanel> return Error; }}测试
[*]小于下限时，出现红色文字提示，ToolTip 提示 "Value out of lower limit range in viewmodel."
[*]大于上限时，出现红色文字提示，ToolTip 提示 "Value out of upper limit range in viewmodel."
小结
以上两种数据校验（IDataErrorInfo、ValidationRule）的方式，均可以实现自定义数据校验，例如对数据的格式、范围、逻辑等方面的验证，并在验证失败时提供相应的反馈信息。
ValidationRule适用于在界面做数据校验，且可以定义多个校验规则。
ValidationRule适用于在ViewModel做数据校验，可以做一些无法在前端页面做的事情，比如出现异常值是还原为默认值。
所以两者既可以单独使用，也可以组合使用，即使使用MVVM模式，依旧能够优雅的做数据校验。
来源:https://www.cnblogs.com/pandefu/archive/2023/11/16/17837358.html
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