《深入浅出WPF》读书笔记.6binding系统(下)

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《深入浅出WPF》读书笔记.6binding系统(下)

背景

主要讲数据校验和数据转换以及multibinding

代码

binding的数据校验

<Window x:Class="BindingSysDemo.ValidationRulesDemo"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:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"xmlns:local="clr-namespace:BindingSysDemo"mc:Ignorable="d"Title="ValidationRulesDemo" Height="200" Width="400"><StackPanel VerticalAlignment="Center"><TextBox x:Name="tb1" Margin="5"></TextBox><Slider x:Name="sld1" Minimum="-10" Maximum="110" Margin="5"></Slider></StackPanel>
</Window>

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.Shapes;namespace BindingSysDemo
{/// <summary>/// ValidationRulesDemo.xaml 的交互逻辑/// </summary>public partial class ValidationRulesDemo : Window{public ValidationRulesDemo(){InitializeComponent();Binding binding = new Binding("Value") { Source = this.sld1, UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged };RangeValidationRule rule = new RangeValidationRule();//此参数用来校验source数据rule.ValidatesOnTargetUpdated = true;binding.ValidationRules.Add(rule);//通过路由事件获取校验的报错信息//信号在UI树上传递的过程乘坐路由事件binding.NotifyOnValidationError = true;this.tb1.SetBinding(TextBox.TextProperty, binding);//监听校验失败错误this.tb1.AddHandler(Validation.ErrorEvent, new RoutedEventHandler(this.ValidationError));}private void ValidationError(object sender, RoutedEventArgs e){if (Validation.GetErrors(this.tb1).Count > 0){this.tb1.ToolTip = Validation.GetErrors(this.tb1)[0].ErrorContent.ToString();}}}
}

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Controls;namespace BindingSysDemo
{public class RangeValidationRule : ValidationRule{public override ValidationResult Validate(object value, CultureInfo cultureInfo){//throw new NotImplementedException();double d = 0;if (double.TryParse(value.ToString(), out d)){if (d >= 0 && d <= 100){return new ValidationResult(true, null);}}return new ValidationResult(false, "Validation failed!");}}
}

binding的数据转换

<Window x:Class="BindingSysDemo.BindingConverterDemo"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:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"xmlns:local="clr-namespace:BindingSysDemo"mc:Ignorable="d"Title="BindingConverterDemo" Height="500" Width="600"><Window.Resources><local:Category2SourceConverter x:Key="c2s"></local:Category2SourceConverter><local:State2NullableBoolConverter x:Key="s2b"></local:State2NullableBoolConverter></Window.Resources><StackPanel Background="AliceBlue"><ListBox x:Name="listBoxPlane" Height="300" Margin="5"><ListBox.ItemTemplate><DataTemplate><StackPanel Orientation="Horizontal"><Image Width="40" Height="20" Source="{Binding Path=Category, Converter={StaticResource c2s}}"></Image><TextBlock Text="{Binding Path=Name}" Width="60" Margin="80,0"></TextBlock><CheckBox IsThreeState="True" IsChecked="{Binding Path=State, Converter={StaticResource s2b}}"></CheckBox></StackPanel></DataTemplate></ListBox.ItemTemplate></ListBox><Button x:Name="btnLoad" Content="Load" Height="25" Margin="5" Click="btnLoad_Click"></Button><Button x:Name="btnSave" Content="Save" Height="25" Margin="5" Click="btnSave_Click"></Button></StackPanel>
</Window>

using System;
using System.Collections.Generic;
using System.IO;
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.Shapes;namespace BindingSysDemo
{/// <summary>/// BindingConverterDemo.xaml 的交互逻辑/// </summary>public partial class BindingConverterDemo : Window{public BindingConverterDemo(){InitializeComponent();}private void btnLoad_Click(object sender, RoutedEventArgs e){List<Plane> planes = 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 = planes;}private void btnSave_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(AppDomain.CurrentDomain.BaseDirectory + "PlaneList.txt", sb.ToString());MessageBox.Show("保存成功!");}}public enum Category{Bomber,Fighter}public enum State{Available,Locked,Unknown}public class Plane{public Category Category { get; set; }public State State { get; set; }public string Name { get; set; }}}

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Data;namespace BindingSysDemo
{public class Category2SourceConverter : IValueConverter{//将Category转换成Uripublic object Convert(object value, Type targetType, object parameter, CultureInfo culture){Category category = (Category)value;switch (category){case Category.Fighter:return @"\Icon\Fighter.png";case Category.Bomber:return @"\Icon\Bomber.png";default:return null;}}//不会被调用public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture){throw new NotImplementedException();}}public class State2NullableBoolConverter : IValueConverter{//将State转换成boolpublic object Convert(object value, Type targetType, object parameter, CultureInfo culture){State state = (State)value;switch (state){case State.Locked:return false;case State.Available:return true;case State.Unknown:default:return null;}}//不会被调用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;}}}
}

multibinding

当页面显示信息不仅由一个控件来决定，就可以使用multibinding。凡是使用binding的地方都可以使用multibinding

<Window x:Class="BindingSysDemo.MultiBindingDemo"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:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"xmlns:local="clr-namespace:BindingSysDemo"mc:Ignorable="d"Title="MultiBindingDemo" Height="400" Width="600"><StackPanel><TextBox x:Name="tb1" Height="23" Margin="5"></TextBox><TextBox x:Name="tb2" Height="23" Margin="5"></TextBox><TextBox x:Name="tb3" Height="23" Margin="5"></TextBox><TextBox x:Name="tb4" Height="23" Margin="5"></TextBox><Button x:Name="btn1" Content="Submit" Width="80" Margin="5"></Button></StackPanel>
</Window>

using System;
using System.Collections.Generic;
using System.Globalization;
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.Shapes;namespace BindingSysDemo
{/// <summary>/// MultiBindingDemo.xaml 的交互逻辑/// </summary>public partial class MultiBindingDemo : Window{public MultiBindingDemo(){InitializeComponent();this.SetMultiBinding();}private void SetMultiBinding(){//准备基础bindingBinding b1 = new Binding("Text") { Source = this.tb1 };Binding b2 = new Binding("Text") { Source = this.tb2 };Binding b3 = new Binding("Text") { Source = this.tb3 };Binding b4 = new Binding("Text") { Source = this.tb4 };//multibindingMultiBinding mb = new MultiBinding();mb.Bindings.Add(b1);mb.Bindings.Add(b2);mb.Bindings.Add(b3);mb.Bindings.Add(b4);mb.Converter = new LoginMultiBindingConverter();this.btn1.SetBinding(Button.IsEnabledProperty, mb);}}public class LoginMultiBindingConverter : IMultiValueConverter{public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture){if (!values.Cast<string>().Any(o => string.IsNullOrEmpty(o)) && values[0].ToString() == values[2].ToString()&& values[1].ToString() == values[3].ToString()){return true;}return false;}public object[] ConvertBack(object value, Type[] targetType, object parameter, CultureInfo culture){throw new NotImplementedException();}}}

git代码

GitHub - wanghuayu-hub2021/WpfBookDemo: 深入浅出WPF的demo

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