1、ValidationRule 驗(yàn)證ValidationRule：是通過(guò)ValidationRule中的的Validate方法來(lái)驗(yàn)證我們綁定的屬性。所以我們的用法是繼承ValidationRule，重寫他的Validate方法。示例 public class RequiredRule : ValidationRule
{
public override ValidationResult Validate(object value, CultureInfo cultureInfo)
{
if (value == null)
return new ValidationResult(false, "不能為空值！");
if (string.IsNullOrEmpty(value.ToString()))
return new ValidationResult(false, "不能為空字符串！");
return new ValidationResult(true, null);
}
}
而XAML中需要把錯(cuò)誤信息顯示出來(lái)。 <Window.Resources>
<ControlTemplate x:Key="ErrorTemplate">
<Border BorderBrush="Red" BorderThickness="1">
<AdornedElementPlaceholder/>
</Border>
</ControlTemplate>
<Style TargetType="TextBox">
<Setter Property="Validation.ErrorTemplate" Value="{StaticResource ErrorTemplate}">
</Setter>
<Style.Triggers>
<Trigger Property="Validation.HasError" Value="True">
<Setter Property="ToolTip" Value="{Binding RelativeSource={RelativeSource Self}, Path=(Validation.Errors)[0].ErrorContent}"/>
</Trigger>
</Style.Triggers>
</Style>
</Window.Resources>
<StackPanel>
<TextBlock Text="姓名"/>
<TextBox>
<TextBox.Text>
<Binding Path="Name" UpdateSourceTrigger="PropertyChanged" ValidatesOnDataErrors="True">
<Binding.ValidationRules>
<ValidationRules:RequiredRule/>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>
<TextBlock Text="年齡"/>
<TextBox >
<TextBox.Text>
<Binding Path="Age" UpdateSourceTrigger="PropertyChanged" ValidatesOnDataErrors="True">
<Binding.ValidationRules>
<ValidationRules:GreaterThanRule Number="10"/>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>
</StackPanel>
這樣顯示的錯(cuò)誤信息就會(huì)以 ToolTip和紅色邊框的形式顯示出來(lái)。但這邊如果又在TextBox里面設(shè)置ToolTip那么就會(huì)優(yōu)先選擇TextBox里的，也就是Style中的ToolTip遇到錯(cuò)誤信息是不會(huì)顯示出來(lái)的，而是顯示TextBox中的ToolTip。所以我們可以改善一下顯示的模版來(lái)解決這個(gè)問(wèn)題。 <ControlTemplate x:Key="ErrorTemplate">
<DockPanel LastChildFill="true">
<Border Background="Red" DockPanel.Dock="right" Margin="5,0,0,0" Width="20" Height="20" CornerRadius="10"
ToolTip="{Binding ElementName=customAdorner, Path=AdornedElement.(Validation.Errors)[0].ErrorContent}">
<TextBlock Text="!" VerticalAlignment="center" HorizontalAlignment="center" FontWeight="Bold" Foreground="white">
</TextBlock>
</Border>
<AdornedElementPlaceholder Name="customAdorner" VerticalAlignment="Center" >
<Border BorderBrush="red" BorderThickness="1" />
</AdornedElementPlaceholder>
</DockPanel>
</ControlTemplate>
2、Exception 驗(yàn)證Exception ：我們xaml中綁定的對(duì)象是屬性。所以Exception驗(yàn)證，就是通過(guò)屬性的改變來(lái)判斷是否正常。如： public int Age
{
get { return _age; }
set
{
if (value > 200)
{
throw new Exception("年齡不能大于200");
}
_age = value;
}
}
同樣跑出的異常在Xaml中也要顯示下。XAML同上。這種方式就會(huì)破壞POCO的設(shè)計(jì)原則。 3、IDataErrorInfo 驗(yàn)證IDataErrorInfo：這個(gè)驗(yàn)證是通過(guò)我們的實(shí)體對(duì)象繼承IDataErrorInfo來(lái)實(shí)現(xiàn)的。這里聲明的this索引器來(lái)訪問(wèn)類的成員。 public class BaseDataErrorInfo : IDataErrorInfo
{
private string _error;
public string this[string columnName]
{
get { return GetErrorFor(columnName); }
}
public string Error
{
get { return _error; }
set { _error = value; }
}
public virtual string GetErrorFor(string columnName)
{
return string.Empty;
}
}
public class Person : BaseDataErrorInfo
{
public string Name { get; set; }
public override string GetErrorFor(string columnName)
{
if (columnName == "Name")
if (string.IsNullOrEmpty(Name))
return "Name 不能為空";
return base.GetErrorFor(columnName);
}
}
XAML同上。 4、Custom Control 驗(yàn)證這里我即不想污染實(shí)體類，又想實(shí)現(xiàn)一個(gè)通用的Validate。我想通過(guò)我xaml綁定的屬性和它所屬的控件。來(lái)顯示ToolTip。 public abstract class Validator : FrameworkElement
{
static Validator()
{
DefaultStyleKeyProperty.OverrideMetadata(typeof(Validator), new FrameworkPropertyMetadata(typeof(Validator)));
}
public virtual string ErrorMessage { get { return string.Empty; } }
public abstract bool InitialValidation();
public FrameworkElement ElementName
{
get { return (FrameworkElement)GetValue(ElementNameProperty); }
set { SetValue(ElementNameProperty, value); }
}
// Using a DependencyProperty as the backing store for ElementName. This enables animation, styling, binding, etc...
public static readonly DependencyProperty ElementNameProperty =
DependencyProperty.Register("ElementName", typeof(FrameworkElement), typeof(Validator), new PropertyMetadata(null));
public object Source
{
get { return (object)GetValue(SourceProperty); }
set { SetValue(SourceProperty, value); }
}
// Using a DependencyProperty as the backing store for Source. This enables animation, styling, binding, etc...
public static readonly DependencyProperty SourceProperty =
DependencyProperty.Register("Source", typeof(object), typeof(Validator), new UIPropertyMetadata(new PropertyChangedCallback(ValidPropertyPropertyChanged)));
private static void ValidPropertyPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var validator = d as Validator;
if (validator != null)
validator.SetSourceFromProperty();
if (string.IsNullOrEmpty(e.NewValue.ToString()))
{
if (validator != null)
{
validator.IsValid = validator.InitialValidation();
if (validator.ElementName.DataContext != null)
validator.ShowToolTip();
validator.IsValid = false;
}
}
}
private void ShowToolTip()
{
if (IsValid)
{
timer = new DispatcherTimer();
timer.Interval = TimeSpan.FromSeconds(1.5);
_toolTip = new ToolTip();
_toolTip.StaysOpen = true;
_toolTip.PlacementTarget = ElementName;
_toolTip.Placement = PlacementMode.Right;
_toolTip.Content = ErrorMessage;
_toolTip.IsOpen = true;
timer.Tick += (sender, args) =>
{
_toolTip.IsOpen = false;
timer.Stop();
};
timer.Start();
}
}
private void SetSourceFromProperty()
{
var expression = this.GetBindingExpression(SourceProperty);
if (expression != null && this.ElementName == null)
this.SetValue(Validator.ElementNameProperty, expression.DataItem as FrameworkElement);
}
private ToolTip _toolTip;
private DispatcherTimer timer;
public bool IsValid { get; set; }
}
這是一個(gè)簡(jiǎn)單的Validate基類。提供思想。功能不完善。 然后繼承這個(gè)Validator public class RequiredValidator : Validator
{
public override string ErrorMessage { get { return "不能為空值"; } }
public override bool InitialValidation()
{
if (Source == null)
return false;
return string.IsNullOrEmpty(Source.ToString());
}
}
這里ErrorMessage是顯示錯(cuò)誤信息。 InitialValidation方法是我們要驗(yàn)證的規(guī)則。 代碼 關(guān)于使用的小例子： 一、通過(guò)代碼實(shí)現(xiàn)數(shù)據(jù)綁定通過(guò)代碼實(shí)現(xiàn)數(shù)據(jù)綁定，使用的是System.Windows.Data命名空間的Binding類，主要使用Binding類的如下的屬性：
在綁定目標(biāo)控件上使用SetBinding方法添加數(shù)據(jù)綁定。例如將MyData的Name屬性綁定到txtName控件的Text屬性上，使用MyColorConverter轉(zhuǎn)換器將MyBindingColor的ColorObject屬性綁定到rec控件的Fill屬性上： 1: MyData data = new MyData(); 2: 3: Binding binding1 = new Binding(); 4: binding1.Source = data; 5: binding1.Mode = BindingMode.OneWay; 6: binding1.Path = new PropertyPath("Name");
7: 8: txtName.SetBinding(TextBox.TextProperty, binding1); 9: 10: 11: MyBindingColor color = new MyBindingColor(); 12: 13: Binding binding2 = new Binding(); 14: binding2.Source = color; 15: binding2.Mode = BindingMode.OneWay; 16: binding2.Path = new PropertyPath("ColorObject");
17: binding2.Converter = new MyColorConverter(); 18: 19: rec.SetBinding(Rectangle.FillProperty, binding2); 二、實(shí)現(xiàn)綁定數(shù)據(jù)的驗(yàn)證：對(duì)于綁定數(shù)據(jù)的驗(yàn)證，系統(tǒng)采用如下的機(jī)制：
使用 WPF 數(shù)據(jù)綁定模型可以將 ValidationRules 與 Binding 對(duì)象相關(guān)聯(lián)。當(dāng)綁定目標(biāo)的屬性向綁定源屬性傳遞屬性值時(shí)（僅限TwoWay模式或OneWayToSource模式），執(zhí)行ValidationRule中的Validate方法，實(shí)現(xiàn)對(duì)界面輸入數(shù)據(jù)的驗(yàn)證。 定義驗(yàn)證可以采用以下三種：
例如，定義一個(gè)學(xué)生信息類，要求其學(xué)生成績(jī)?cè)?到100間，學(xué)生姓名的長(zhǎng)度在2到10個(gè)字符間： 1: public class StudentInfoWithValidation : IDataErrorInfo 2: {
3: #region 構(gòu)造方法 4: public StudentInfoWithValidation() 5: {
6: StudentName = "Tom"; 7: Score = 90; 8: } 9: public StudentInfoWithValidation(string m_StudentName,double m_Score) 10: {
11: StudentName = m_StudentName; 12: Score = m_Score; 13: } 14: #endregion 15: 16: #region 屬性 17: public string StudentName 18: {
19: get; set; 20: } 21: public double Score 22: {
23: get; set; 24: } 25: #endregion 26: 27: #region 實(shí)現(xiàn)IDataErrorInfo接口的成員 28: public string Error 29: {
30: get 31: {
32: return null; 33: } 34: } 35: 36: public string this[string columnName] 37: {
38: get 39: {
40: string result = null; 41: 42: switch (columnName) 43: {
44: case "StudentName": 45: // 設(shè)置StudentName屬性的驗(yàn)證規(guī)則 46: int len = StudentName.Length; 47: if (len < 2 || len > 10) 48: {
49: result = "StudentName length must between 2 and 10"; 50: } 51: break; 52: case "Score": 53: // 設(shè)置Score屬性的驗(yàn)證規(guī)則 54: if (Score < 0 || Score > 100) 55: {
56: result = "Score must between 0 and 100"; 57: } 58: break; 59: } 60: 61: return result; 62: } 63: } 64: #endregion 65: } 在界面上，定義兩個(gè)TextBox綁定到StudentName和Score兩個(gè)屬性上，并設(shè)置其采用DataErrorValidationRule： 1: <Window x:Class="WPFDataBindingDemo.WinDataErrorValidationRuleDemo" 2: xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 3: xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 4: xmlns:local="clr-namespace:WPFDataBindingDemo" 5: Title="WinDataErrorValidationRuleDemo" Height="154" Width="300"> 6: <Canvas Height="116" x:Name="mainCanvas"> 7: <Canvas.Resources> 8: <local:StudentInfoWithValidation x:Key="myData" /> 9: </Canvas.Resources> 10: <Canvas.DataContext> 11: <Binding Source="{StaticResource myData}" />
12: </Canvas.DataContext> 13: <Label Canvas.Left="10" Canvas.Top="10" Height="28" Name="label1" Width="120">StudentName:</Label> 14: <Label Canvas.Left="10" Canvas.Top="36" Height="28" Name="label2" Width="120">Score:</Label> 15: <TextBox Canvas.Left="136" Canvas.Top="12" Height="23" Name="textBox1" Width="120"> 16: <TextBox.Text> 17: <Binding Path="StudentName" 18: Mode="TwoWay" 19: UpdateSourceTrigger="PropertyChanged" 20: ValidatesOnDataErrors="True" /> 21: </TextBox.Text> 22: </TextBox> 23: <TextBox Canvas.Left="136" Canvas.Top="41" Height="23" Name="textBox2" Width="120"> 24: <TextBox.Text> 25: <Binding Path="Score" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged"> 26: <!--與上一個(gè)TextBox控件的寫法作用相同--> 27: <Binding.ValidationRules> 28: <DataErrorValidationRule /> 29: </Binding.ValidationRules> 30: </Binding> 31: </TextBox.Text> 32: </TextBox> 33: <Button Canvas.Left="12" Canvas.Top="79" Height="23" Name="button1" Width="118" Click="button1_Click">Get Student Info</Button> 34: <Button Canvas.Left="136" Canvas.Top="79" Height="23" Name="button2" Width="118" Click="button2_Click">Get Validate State</Button> 35: </Canvas> 36: </Window>
從執(zhí)行的結(jié)果上來(lái)看，當(dāng)驗(yàn)證出現(xiàn)錯(cuò)誤（即索引器屬性返回的字符串不為空時(shí)），系統(tǒng)默認(rèn)給出一種驗(yàn)證錯(cuò)誤的顯示方式（控件以紅色邊框包圍），但是需注意兩點(diǎn)：
例如上例中，對(duì)于Score對(duì)應(yīng)的TextBox，再加入ExceptionValidationRule： 1: <TextBox Canvas.Left="136" Canvas.Top="41" Height="23" Name="textBox2" Width="120"> 2: <TextBox.Text> 3: <Binding Path="Score" Mode="TwoWay" UpdateSourceTrigger="PropertyChanged"> 4: <!--與上一個(gè)TextBox控件的寫法作用相同--> 5: <Binding.ValidationRules> 6: <DataErrorValidationRule /> 7: <ExceptionValidationRule /> 8: </Binding.ValidationRules> 9: </Binding> 10: </TextBox.Text> 11: </TextBox>
例如，定義一個(gè)類，用來(lái)驗(yàn)證輸入的Email地址是否合法（驗(yàn)證的Email允許為字符串的空值String.Empty，但有輸入必須符合Email的格式要求） 在學(xué)生類中添加Email可讀可寫屬性（并不做相應(yīng)的驗(yàn)證，忽略其他重復(fù)代碼）： 1: public string Email 2: {
3: set; get; 4: } 定義一個(gè)類，實(shí)現(xiàn)Email格式驗(yàn)證： 1: using System.Globalization; 2: using System.Text.RegularExpressions; 3: using System.Windows.Controls; 4: 5: namespace WPFDataBindingDemo 6: {
7: public class EmailValidationRule : ValidationRule 8: {
9: public override ValidationResult Validate(object value, CultureInfo cultureInfo) 10: {
11: bool isValid = false; 12: string message = null; 13: 14: // 檢查輸入值不為空，且是字符串 15: if (value != null && value is string) 16: {
17: string email = value.ToString(); 18: 19: // 檢查輸入的字符串是否為String.Empty 20: if (email != string.Empty) 21: {
22: string emailFormartRegex = 23: @"^([\w-\.]+)@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.)|" +
24: @"(([\w-]+\.)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$";
25: 26: // 檢查輸入的字符串是否符合Email格式 27: isValid = Regex.IsMatch(email, emailFormartRegex); 28: 29: if (! isValid) 30: {
31: message = "Input string not match Email Format"; 32: } 33: } 34: else 35: {
36: // 輸入的字符串為字符串空值時(shí)，認(rèn)為驗(yàn)證通過(guò) 37: isValid = true; 38: } 39: } 40: else 41: {
42: message = "Input value is NULL or is not string."; 43: } 44: 45: // 返回驗(yàn)證結(jié)果（ValidationResult對(duì)象） 46: return new ValidationResult(isValid,message); 47: } 48: } 49: } 在界面上： 1: <TextBox Canvas.Left="104" Canvas.Top="70" Height="23" Name="textBox3" Width="152"> 2: <Binding Mode="TwoWay" Path="Email" UpdateSourceTrigger="PropertyChanged"> 3: <Binding.ValidationRules> 4: <local:EmailValidationRule /> 5: </Binding.ValidationRules> 6: </Binding> 7: </TextBox>
三、為數(shù)據(jù)驗(yàn)證提供視覺(jué)效果在數(shù)據(jù)驗(yàn)證錯(cuò)誤后，可以通過(guò)以下兩種方式提供相應(yīng)的視覺(jué)效果：
如果要使輸入的控件的外觀發(fā)生變化，可以使用Style。例如上例中出錯(cuò)，使輸入的文本框的背景顏色和字體顏色發(fā)生變化，并提供ToolTip顯示錯(cuò)誤信息，可以定義如下的Style： 1: <Style TargetType="TextBox"> 2: <Setter Property="Background" Value="White" /> 3: <Setter Property="Foreground" Value="Black" /> 4: <Style.Triggers> 5: <Trigger Property="Validation.HasError" Value="True"> 6: <Setter Property="Background" Value="#DDD" /> 7: <Setter Property="Foreground" Value="Red" /> 8: <Setter Property="ToolTip" 9: Value="{Binding RelativeSource={RelativeSource Self},Path=(Validation.Errors)[0].ErrorContent}"/>
10: </Trigger> 11: </Style.Triggers> 12: </Style> 效果如下：
如果要為相應(yīng)的控件添加一些輔助的控件，可以使用控件模板，如出現(xiàn)驗(yàn)證錯(cuò)誤時(shí)，不使用系統(tǒng)默認(rèn)的紅色邊框，而是在文本框后添加一個(gè)紅色的星號(hào)： 1: <ControlTemplate x:Key="validErrorTextBoxTemplate"> 2: <DockPanel> 3: <AdornedElementPlaceholder/> 4: <TextBlock Foreground="Red" FontSize="20">*</TextBlock> 5: </DockPanel> 6: </ControlTemplate> 并在每一個(gè)輸入的TextBox中添加： 1: Validation.ErrorTemplate="{StaticResource validErrorTextBoxTemplate}"
轉(zhuǎn)自：https://www.cnblogs.com/fuchongjundream/p/3844051.html |
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