C# MVVM中的Binding Validation.HasError属性
我目前正在实现一个C# MVVM中的Binding Validation.HasError属性,c#,wpf,validation,mvvm,binding,C#,Wpf,Validation,Mvvm,Binding,我目前正在实现一个ValidationRule，以检查文本框中是否有无效字符。我很高兴在我的文本框中设置我所实现的继承ValidationRule的类，在找到此类字符时将其设置为红色，但是我还想使用Validation.HasError属性或Validation.Errors属性弹出一个消息框，告诉用户页面中的各个文本框中存在错误 是否有方法将myViewModel中的属性绑定到Validation.HasError和/或Validation.Errors属性，以便我可以在我的ViewModel
ValidationRuleValidationRuleValidation.HasErrorViewModel<Style x:Key="ErrorValidationTextBox" TargetType="{x:Type pres:OneTextBox}">
<Setter Property="Validation.ErrorTemplate">
<Setter.Value>
<ControlTemplate>
<DockPanel LastChildFill="True">
<TextBlock DockPanel.Dock="Right"
Foreground="Red"
FontSize="12pt"
Text="{Binding ElementName=MyAdorner,
Path=AdornedElement.(Validation.Errors)[0].ErrorContent}">
</TextBlock>
<AdornedElementPlaceholder x:Name="MyAdorner"/>
</DockPanel>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
<pres:OneTextBox Watermark="Name..." Margin="85,12,0,0" Style="{StaticResource ErrorValidationTextBox}"
AcceptsReturn="False" MaxLines="1" Height="22" VerticalAlignment="Top"
HorizontalAlignment="Left" Width="300" >
<pres:OneTextBox.Text>
<Binding Path="InterfaceSpecification.Name" UpdateSourceTrigger="PropertyChanged">
<Binding.ValidationRules>
<interfaceSpecsModule:NoInvalidCharsRule/>
</Binding.ValidationRules>
</Binding>
</pres:OneTextBox.Text>
</pres:OneTextBox>
Validation.HasError是只读属性，因此
绑定C#VB.NETXAML<Window x:Class="HasErrorTestValidation.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:HasErrorTestValidation"
WindowStartupLocation="CenterScreen"
Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
<local:TestData />
</Window.DataContext>
<StackPanel>
<TextBox x:Name="TestTextBox"
local:ProtocolSettingsLayout.MVVMHasError="{Binding Path=HasError}">
<TextBox.Text>
<Binding Path="TestText" UpdateSourceTrigger="PropertyChanged">
<Binding.ValidationRules>
<local:OnlyNumbersValidationRule ValidatesOnTargetUpdated="True"/>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>
<TextBlock>
<TextBlock.Text>
<Binding Path="HasError" StringFormat="HasError is {0}"/>
</TextBlock.Text>
</TextBlock>
<TextBlock>
<TextBlock.Text>
<Binding Path="(Validation.HasError)" ElementName="TestTextBox" StringFormat="Validation.HasError is {0}"/>
</TextBlock.Text>
</TextBlock>
</StackPanel>
</Window>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
}
}
#region Model
public class TestData : INotifyPropertyChanged
{
private bool _hasError = false;
public bool HasError
{
get
{
return _hasError;
}
set
{
_hasError = value;
NotifyPropertyChanged("HasError");
}
}
private string _testText = "0";
public string TestText
{
get
{
return _testText;
}
set
{
_testText = value;
NotifyPropertyChanged("TestText");
}
}
#region PropertyChanged
public event PropertyChangedEventHandler PropertyChanged;
protected void NotifyPropertyChanged(string sProp)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(sProp));
}
}
#endregion
}
#endregion
#region ValidationRule
public class OnlyNumbersValidationRule : ValidationRule
{
public override ValidationResult Validate(object value, CultureInfo cultureInfo)
{
var result = new ValidationResult(true, null);
string NumberPattern = @"^[0-9-]+$";
Regex rgx = new Regex(NumberPattern);
if (rgx.IsMatch(value.ToString()) == false)
{
result = new ValidationResult(false, "Must be only numbers");
}
return result;
}
}
#endregion
public class ProtocolSettingsLayout
{
public static readonly DependencyProperty MVVMHasErrorProperty= DependencyProperty.RegisterAttached("MVVMHasError",
typeof(bool),
typeof(ProtocolSettingsLayout),
new FrameworkPropertyMetadata(false,
FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
null,
CoerceMVVMHasError));
public static bool GetMVVMHasError(DependencyObject d)
{
return (bool)d.GetValue(MVVMHasErrorProperty);
}
public static void SetMVVMHasError(DependencyObject d, bool value)
{
d.SetValue(MVVMHasErrorProperty, value);
}
private static object CoerceMVVMHasError(DependencyObject d,Object baseValue)
{
bool ret = (bool)baseValue;
if (BindingOperations.IsDataBound(d,MVVMHasErrorProperty))
{
if (GetHasErrorDescriptor(d)==null)
{
DependencyPropertyDescriptor desc = DependencyPropertyDescriptor.FromProperty(Validation.HasErrorProperty, d.GetType());
desc.AddValueChanged(d,OnHasErrorChanged);
SetHasErrorDescriptor(d, desc);
ret = System.Windows.Controls.Validation.GetHasError(d);
}
}
else
{
if (GetHasErrorDescriptor(d)!=null)
{
DependencyPropertyDescriptor desc= GetHasErrorDescriptor(d);
desc.RemoveValueChanged(d, OnHasErrorChanged);
SetHasErrorDescriptor(d, null);
}
}
return ret;
}
private static readonly DependencyProperty HasErrorDescriptorProperty = DependencyProperty.RegisterAttached("HasErrorDescriptor",
typeof(DependencyPropertyDescriptor),
typeof(ProtocolSettingsLayout));
private static DependencyPropertyDescriptor GetHasErrorDescriptor(DependencyObject d)
{
var ret = d.GetValue(HasErrorDescriptorProperty);
return ret as DependencyPropertyDescriptor;
}
private static void OnHasErrorChanged(object sender, EventArgs e)
{
DependencyObject d = sender as DependencyObject;
if (d != null)
{
d.SetValue(MVVMHasErrorProperty, d.GetValue(Validation.HasErrorProperty));
}
}
private static void SetHasErrorDescriptor(DependencyObject d, DependencyPropertyDescriptor value)
{
var ret = d.GetValue(HasErrorDescriptorProperty);
d.SetValue(HasErrorDescriptorProperty, value);
}
}
ValidationRule针对安纳托利提出的非工作项目示例请求： Generic.xaml HasErrorUtility.cs ViewModel.cs MainWindow.xaml
绑定时所有完美工作集
NotifyOnValidationError=“True”<Button IsEnabled="{Binding ElementName=tbPeriod, Path=(Validation.HasError)}"
只是好奇：您是否有意在视图和视图模型之间传播验证逻辑？@AndreasH。是的，与我的验证规则一样，唯一发生的事情是文本框的边框变为红色。它不会阻止用户输入更多字符（即使当存在无效字符时，Name属性停止更新），也不会阻止用户使用该名称创建InterfaceSpecification。我可以在表单的“提交”按钮上绑定Validation.HasError，但我使用的是自定义框架，无法访问该按钮（不幸的是，它在表单控件中是私有的）。谢谢您的回答！至于IDataErrorInfo，我已经对它进行了一些研究，但据我所知，最终结果与ValidationRule相同：它只在视图中向用户显示存在错误，它不会阻止用户继续程序流，直到错误得到解决。而且，正如我在我的问题中所做的评论中提到的，我使用的是一个自定义框架，它不允许我访问表单的“提交”按钮，因此当不幸出现错误时，我自己无法禁用该按钮（这就是我试图找到解决方法的原因）.@choub890:如果新值无效，您可以阻止在setter中设置viewmodel的值，但会引发INotifyPropertyChanged事件，因此文本框会使用未更改的旧值进行更新。这在普通xaml中可以正常工作，但在自定义控件中，当我尝试使用模板绑定绑定附加属性时，强制emvvmhasserror（…）中的BindingOperations.IsDataBound（d，MVVMHasErrorProperty）调用返回false，因此永远不会安装回调。关于如何在自定义控件中工作，你有什么想法吗？@Brian Stewart:你能给出一个非工作项目的具体例子吗？时间会怎样，我会看的。@Anatoliy Nikolaev：我添加了一个示例作为这个问题的答案，说明您的技术使用标准XAML，而当XAML放在自定义控件中时不起作用。谢谢我不太理解您的示例。Validation.HasError
在使用ValidationRule
时主要需要，在您的示例中则不是。此外，在我的计算机（Windows 7）中，这两个示例在强制（）函数中都返回false。此示例的含义是，绑定
在默认情况下不在验证中工作。HasError
，因为此属性不是依赖属性，此示例弥补了此缺点。此外，在自定义控件中，只需将bool值分配给依赖项属性->在这种情况下，通常不会在HasErrorUtility中调用强制函数。
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:TestAttachedPropertyValidationError">
<Style TargetType="{x:Type local:TextBoxCustomControl}">
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type local:TextBoxCustomControl}">
<Border Background="{TemplateBinding Background}"
BorderBrush="{TemplateBinding BorderBrush}"
BorderThickness="{TemplateBinding BorderThickness}">
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="10"/>
<ColumnDefinition Width="50"/>
</Grid.ColumnDefinitions>
<Grid.Resources>
<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
</Grid.Resources>
<Label
Grid.Row ="0"
Grid.Column="0"
Content="Enter a numeric value:" />
<TextBox
Grid.Row ="0"
Grid.Column="2"
local:HasErrorUtility.HasError="{Binding NumericPropHasError, Mode=TwoWay, RelativeSource={RelativeSource TemplatedParent}}"
Text="{Binding NumericProp, Mode=TwoWay, UpdateSourceTrigger=LostFocus, RelativeSource={RelativeSource TemplatedParent}}" />
<Label
Grid.Row ="1"
Grid.Column="0"
Content="Value entered:" />
<Label
Grid.Row ="1"
Grid.Column="2"
Content="{TemplateBinding NumericProp}" />
<Label
Grid.Row ="2"
Grid.Column="0"
Grid.ColumnSpan="3"
Visibility="{TemplateBinding NumericPropHasError, Converter={StaticResource BooleanToVisibilityConverter}}"
Foreground="Red"
Content="Not a numeric value" />
</Grid>
</Border>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
using System.Windows;
using System.Windows.Controls;
namespace TestAttachedPropertyValidationError
{
public class TextBoxCustomControl : Control
{
static TextBoxCustomControl()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(TextBoxCustomControl), new FrameworkPropertyMetadata(typeof(TextBoxCustomControl)));
}
public static readonly DependencyProperty NumericPropProperty =
DependencyProperty.Register("NumericProp", typeof (int), typeof (TextBoxCustomControl), new PropertyMetadata(default(int)));
public int NumericProp
{
get { return (int) GetValue(NumericPropProperty); }
set { SetValue(NumericPropProperty, value); }
}
public static readonly DependencyProperty NumericPropHasErrorProperty =
DependencyProperty.Register("NumericPropHasError", typeof (bool), typeof (TextBoxCustomControl), new PropertyMetadata(default(bool)));
public bool NumericPropHasError
{
get { return (bool) GetValue(NumericPropHasErrorProperty); }
set { SetValue(NumericPropHasErrorProperty, value); }
}
}
}
using System;
using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
namespace TestAttachedPropertyValidationError
{
class HasErrorUtility
{
public static readonly DependencyProperty HasErrorProperty = DependencyProperty.RegisterAttached("HasError",
typeof(bool),
typeof(HasErrorUtility),
new FrameworkPropertyMetadata(false,
FrameworkPropertyMetadataOptions.BindsTwoWayByDefault,
null,
CoerceHasError));
public static bool GetHasError(DependencyObject d)
{
return (bool)d.GetValue(HasErrorProperty);
}
public static void SetHasError(DependencyObject d, bool value)
{
d.SetValue(HasErrorProperty, value);
}
private static object CoerceHasError(DependencyObject d, Object baseValue)
{
var ret = (bool)baseValue;
if (BindingOperations.IsDataBound(d, HasErrorProperty))
{
if (GetHasErrorDescriptor(d) == null)
{
var desc = DependencyPropertyDescriptor.FromProperty(Validation.HasErrorProperty, d.GetType());
desc.AddValueChanged(d, OnHasErrorChanged);
SetHasErrorDescriptor(d, desc);
ret = Validation.GetHasError(d);
}
}
else
{
if (GetHasErrorDescriptor(d) != null)
{
var desc = GetHasErrorDescriptor(d);
desc.RemoveValueChanged(d, OnHasErrorChanged);
SetHasErrorDescriptor(d, null);
}
}
return ret;
}
private static readonly DependencyProperty HasErrorDescriptorProperty = DependencyProperty.RegisterAttached("HasErrorDescriptor",
typeof(DependencyPropertyDescriptor),
typeof(HasErrorUtility));
private static DependencyPropertyDescriptor GetHasErrorDescriptor(DependencyObject d)
{
var ret = d.GetValue(HasErrorDescriptorProperty);
return ret as DependencyPropertyDescriptor;
}
private static void SetHasErrorDescriptor(DependencyObject d, DependencyPropertyDescriptor value)
{
d.SetValue(HasErrorDescriptorProperty, value);
}
private static void OnHasErrorChanged(object sender, EventArgs e)
{
var d = sender as DependencyObject;
if (d != null)
{
d.SetValue(HasErrorProperty, d.GetValue(Validation.HasErrorProperty));
}
}
}
}
using System.ComponentModel;
using System.Runtime.CompilerServices;
namespace TestAttachedPropertyValidationError
{
public class ViewModel :INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private int _vmNumericProp;
private bool _vmNumericPropHasError;
public int VmNumericProp
{
get { return _vmNumericProp; }
set
{
_vmNumericProp = value;
OnPropertyChanged();
}
}
public bool VmNumericPropHasError
{
get { return _vmNumericPropHasError; }
set
{
_vmNumericPropHasError = value;
OnPropertyChanged();
}
}
protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
{
var handler = PropertyChanged;
if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
}
}
}
<Window x:Class="TestAttachedPropertyValidationError.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:TestAttachedPropertyValidationError"
Title="MainWindow" Height="350" Width="525">
<StackPanel Margin="10">
<StackPanel.Resources>
<local:ViewModel x:Key="VM1"/>
<local:ViewModel x:Key="VM2"/>
</StackPanel.Resources>
<Label Content="Custom Control...}"></Label>
<local:TextBoxCustomControl
Margin="10"
DataContext="{StaticResource VM1}"
NumericProp="{Binding VmNumericProp}"
NumericPropHasError="{Binding VmNumericPropHasError}"/>
<Label Content="Regular XAML...}" Margin="0,20,0,0"/>
<Grid
Margin="10"
DataContext="{StaticResource VM2}"
>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="10"/>
<ColumnDefinition Width="50"/>
</Grid.ColumnDefinitions>
<Grid.Resources>
<BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter"/>
</Grid.Resources>
<Label
Grid.Row ="0"
Grid.Column="0"
Content="Enter a numeric value:" />
<TextBox
Grid.Row ="0"
Grid.Column="2"
local:HasErrorUtility.HasError="{Binding VmNumericPropHasError, Mode=TwoWay}"
Text="{Binding VmNumericProp, Mode=TwoWay, UpdateSourceTrigger=LostFocus}" />
<Label
Grid.Row ="1"
Grid.Column="0"
Content="Value entered:" />
<Label
Grid.Row ="1"
Grid.Column="2"
Content="{Binding VmNumericProp}" />
<Label
Grid.Row ="2"
Grid.Column="0"
Grid.ColumnSpan="3"
Visibility="{Binding VmNumericPropHasError, Converter={StaticResource BooleanToVisibilityConverter}}"
Foreground="Red"
Content="Not a numeric value" />
</Grid>
</StackPanel>
<Button IsEnabled="{Binding ElementName=tbPeriod, Path=(Validation.HasError)}"
<TextBox MaxLength="5" x:Name="tbPeriod" HorizontalAlignment="Left" VerticalAlignment="Top" Width="162" Margin="10,10,0,0" Style="{StaticResource TextBoxInError}">
<TextBox.Text>
<Binding Path="ReportPeriod" UpdateSourceTrigger="PropertyChanged" NotifyOnValidationError="True">
<Binding.ValidationRules>
<val:RangeRule Min="70" Max="5000" />
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>