.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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