.NET: WPF Binding对数据的校验和转换以及多路Binding
一。校验
一般需要对target上的值进行校验。
xaml:
<Window x:Class="WpfApplication1.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Simple Binding" Height="135" Width="300"> <StackPanel x:Name="stackPanel" Background="LightBlue"> <TextBox x:Name="textBox1" Margin="5" /> <Slider x:Name="slider1" Minimum="0" Maximum="100" Margin="5" /> </StackPanel> </Window>
写一个RangeValidationRule类
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Controls; namespace WpfApplication1 { class RangeValidationRule : ValidationRule { public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo) { ; if (double.TryParse(value.ToString(), out d)) { && d <= ) { return new ValidationResult(true, null); } } return new ValidationResult(false, "Validation Failed"); } } }
再在xaml.cs里这么写
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; using System.Data; using MySql.Data; using MySql.Data.Entity; using MySql.Data.MySqlClient; using System.Xml; using System.Xml.Linq; namespace WpfApplication1 { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); Binding binding = new Binding("Value") { Source = this.slider1 }; binding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged; RangeValidationRule rvr = new RangeValidationRule(); binding.ValidationRules.Add(rvr); this.textBox1.SetBinding(TextBox.TextProperty, binding); } } }
如果在textbox里的数不在0到100范围里,其边框就会变成红色
在这里Source是slider1,target是textBox1。一般来说Source的数据都是正确的,而target的数据可能是用户输入的,有可能是不正确的,所以需要校验。上面的代码是不会对Source更新数据时进行校验的,如果说Source的数据也有可能有问题,我们就需要将校验条件的ValidatesOnTargetUpdated属性设为true
xaml:
<Window x:Class="WpfApplication1.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" Title="Simple Binding" Height="135" Width="300"> <StackPanel x:Name="stackPanel" Background="LightBlue"> <TextBox x:Name="textBox1" Margin="5" /> <Slider x:Name="slider1" Minimum="-10" Maximum="110" Margin="5" /> </StackPanel> </Window>
xaml.cs:
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; using System.Data; using MySql.Data; using MySql.Data.Entity; using MySql.Data.MySqlClient; using System.Xml; using System.Xml.Linq; namespace WpfApplication1 { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); Binding binding = new Binding("Value") { Source = this.slider1 }; binding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged; RangeValidationRule rvr = new RangeValidationRule(); rvr.ValidatesOnTargetUpdated = true; binding.ValidationRules.Add(rvr); this.textBox1.SetBinding(TextBox.TextProperty, binding); } } }
当slider的值小于0或者大于100时,textbox的边框就会变红,数字是不在0到100内的
如果要显示这个错误信息,需要加入侦听器,具体代码如下:
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; using System.Data; using MySql.Data; using MySql.Data.Entity; using MySql.Data.MySqlClient; using System.Xml; using System.Xml.Linq; namespace WpfApplication1 { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); Binding binding = new Binding("Value") { Source = this.slider1 }; binding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged; RangeValidationRule rvr = new RangeValidationRule(); rvr.ValidatesOnTargetUpdated = true; binding.ValidationRules.Add(rvr); binding.NotifyOnValidationError = true; this.textBox1.SetBinding(TextBox.TextProperty, binding); this.textBox1.AddHandler(Validation.ErrorEvent, new RoutedEventHandler(this.ValidationError)); } private void ValidationError(object sender, RoutedEventArgs e) { ) { ].ErrorContent.ToString(); } } } }
二。 转换
简单的转换比如double转string WPF已经帮我们做了,但是像image转Enum之类的需要我们自己去写,我们要写一个类实现IValueConverter接口,里面有两个函数:Convert(source—>target)和ConvertBack(target->source)
先写一个plane类
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; namespace WpfApplication1 { public enum Category { Bomber, Fighter } public enum State { Available, Locked, Unknown } class Plane { public Category Category { get; set; } public string Name { get; set; } public State State { get; set; } } }
再写实现IValueConverter的类
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Data; using System.Globalization; namespace WpfApplication1 { public class CategoryToSourceConverter : IValueConverter { public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { Category c = (Category)value; switch(c) { case Category.Bomber: return @"\Icons\Bomber.jpg"; case Category.Fighter: return @"\Icons\Fighter.jpg"; default: return null; } } public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { throw new NotImplementedException(); } } public class StateToNullableBoolConverter : IValueConverter { public object Convert(object value, Type targetType, object parameter, CultureInfo culture) { State s = (State)value; switch(s) { case State.Locked: return false; case State.Available: return true; case State.Unknown: default: return null; } } public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture) { bool? nb = (bool?)value; switch(nb) { case true: return State.Available; case false: return State.Locked; case null: default: return State.Unknown; } } } }
xaml:
<Window x:Class="WpfApplication1.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:WpfApplication1" Title="Simple Binding" Height="266" Width="300"> <Window.Resources> <local:CategoryToSourceConverter x:Key="cts" /> <local:StateToNullableBoolConverter x:Key="stnb" /> </Window.Resources> <StackPanel x:Name="stackPanel" Background="LightBlue"> <ListBox x:Name="listBoxPlane" Height="160" Margin="5"> <ListBox.ItemTemplate> <DataTemplate> <StackPanel Orientation="Horizontal"> <Image Width="20" Height="20" Source="{Binding Path=Category, Converter={StaticResource cts}}"/> <TextBlock Text="{Binding Path=Name}" Width="60" Margin="80"/> <CheckBox IsThreeState="True" IsChecked="{Binding Path=State, Converter={StaticResource stnb}}"/> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> </ListBox> <Button x:Name="buttonLoad" Content="Load" Height="25" Margin="5" Click="buttonLoad_Click" /> <Button x:Name="buttonSave" Content="Save" Height="25" Margin="5.5" Click="buttonSave_Click" /> </StackPanel> </Window>
xaml.cs
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; using System.Data; using MySql.Data; using MySql.Data.Entity; using MySql.Data.MySqlClient; using System.Xml; using System.Xml.Linq; using System.IO; namespace WpfApplication1 { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); } private void buttonLoad_Click(object sender, RoutedEventArgs e) { List<Plane> planeList = new List<Plane>() { new Plane(){Category=Category.Bomber, Name="B-1", State=State.Unknown}, new Plane(){Category=Category.Bomber, Name="B-2", State=State.Unknown}, new Plane(){Category=Category.Fighter, Name="F-22", State=State.Unknown}, new Plane(){Category=Category.Fighter, Name="Su-47", State=State.Unknown}, new Plane(){Category=Category.Bomber, Name="B-52", State=State.Unknown}, new Plane(){Category=Category.Fighter, Name="J-10", State=State.Unknown}, }; this.listBoxPlane.ItemsSource = planeList; } private void buttonSave_Click(object sender, RoutedEventArgs e) { StringBuilder sb = new StringBuilder(); foreach(Plane p in listBoxPlane.Items) { sb.AppendLine(string.Format("Category={0}, Name={1}, State={2}", p.Category, p.Name, p.State)); } File.WriteAllText(@"C:\Users\Administrator\Desktop\Demo\WpfApplication1\WpfApplication1\PlaneList.txt", sb.ToString()); } } }
三。MultiBinding
这个例子验证textBox1和textBox2是不是相同,textBox3和textBox4是不是相同,如果相同则button is enabled
Converter:
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Data; using System.Globalization; namespace WpfApplication1 { class LoginMultiBindingConverter : IMultiValueConverter { public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture) { if (!values.Cast<string>().Any(text => string.IsNullOrEmpty(text)) && values[].ToString() == values[].ToString() && values[].ToString() == values[].ToString()) { return true; } return false; } public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture) { throw new NotImplementedException(); } } }
xaml:
<Window x:Class="WpfApplication1.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:WpfApplication1" Title="Simple Binding" Height="200" Width="300"> <StackPanel x:Name="stackPanel" Background="LightBlue"> <TextBox x:Name="textBox1" Height="23" Margin="5" /> <TextBox x:Name="textBox2" Height="23" Margin="5" /> <TextBox x:Name="textBox3" Height="23" Margin="5" /> <TextBox x:Name="textBox4" Height="23" Margin="5" /> <Button x:Name="button1" Content="Submit" Width="80" Margin="5"/> </StackPanel> </Window>
xaml.cs:
using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Documents; using System.Windows.Input; using System.Windows.Media; using System.Windows.Media.Imaging; using System.Windows.Navigation; using System.Windows.Shapes; using System.Data; using MySql.Data; using MySql.Data.Entity; using MySql.Data.MySqlClient; using System.Xml; using System.Xml.Linq; using System.IO; namespace WpfApplication1 { /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { public MainWindow() { InitializeComponent(); this.SetMultiBinding(); } private void SetMultiBinding() { Binding b1 = new Binding("Text") { Source = this.textBox1 }; Binding b2 = new Binding("Text") { Source = this.textBox2 }; Binding b3 = new Binding("Text") { Source = this.textBox3 }; Binding b4 = new Binding("Text") { Source = this.textBox4 }; MultiBinding mb = new MultiBinding() { Mode = BindingMode.OneWay }; mb.Bindings.Add(b1); mb.Bindings.Add(b2); mb.Bindings.Add(b3); mb.Bindings.Add(b4); mb.Converter = new LoginMultiBindingConverter(); this.button1.SetBinding(Button.IsEnabledProperty, mb); } } }
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