我今天在工作中遇到了一个问题,其中我有一个同时失败的BindingGroup
多个s。ValidationRule
问题是,当我尝试确定是否有任何错误(即将命令ArgumentException
设置为BindingGroup.ValidateWithoutUpdate
CanExecute
false
我已设法将其提炼为以下示例(抱歉,它仍然跨越多个来源,但我已将所有应复制/粘贴到新 WPF 项目中的相关部分包含在内):
Window1.xaml:
<Window
x:Class="BindingGroupTest.Window1"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:l="clr-namespace:BindingGroupTest"
xmlns:diag="clr-namespace:System.Diagnostics;assembly=WindowsBase"
Title="Window1" Height="300" Width="300">
<Window.BindingGroup>
<BindingGroup Name="RootBindingGroup">
<BindingGroup.ValidationRules>
<l:TestRule1 />
<l:TestRule2 />
</BindingGroup.ValidationRules>
</BindingGroup>
</Window.BindingGroup>
<StackPanel>
<TextBox Text="{Binding
Path=Name,
BindingGroupName=RootBindingGroup,
UpdateSourceTrigger=PropertyChanged,
diag:PresentationTraceSources.TraceLevel=High}" />
<TextBox Text="{Binding
Path=Age,
BindingGroupName=RootBindingGroup,
UpdateSourceTrigger=PropertyChanged,
diag:PresentationTraceSources.TraceLevel=High}" />
<Button Content="Validate" Click="DoValidate" />
</StackPanel>
</Window>
Window1.xaml.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
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;
namespace BindingGroupTest
{
/// <summary>
/// Interaction logic for Window1.xaml
/// </summary>
public partial class Window1 : Window
{
public Window1()
{
this.DataContext = new Person()
{
Name="Test",
Age=30,
};
InitializeComponent();
this.BindingGroup.BeginEdit();
}
private void DoValidate(object sender, RoutedEventArgs e)
{
try
{
if (!this.BindingGroup.ValidateWithoutUpdate())
MessageBox.Show("Validation failed!");
else
MessageBox.Show("Validation passed!");
}
catch (Exception ex)
{
var msg = "While validating, caught exception: " + ex.Message;
MessageBox.Show(msg);
}
}
}
}
个人.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace BindingGroupTest
{
public class Person
{
public string Name { get; set; }
public int Age { get; set; }
}
}
测试规则1.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
namespace BindingGroupTest
{
public class TestRule1 : ValidationRule
{
public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
{
var p = ((BindingGroup)value).Items[0] as Person;
if (p == null)
return ValidationResult.ValidResult;
if (p.Age < 0)
return new ValidationResult(false, "Surely, you've been born yet!");
return ValidationResult.ValidResult;
}
}
}
测试规则2.cs:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
namespace BindingGroupTest
{
public class TestRule2 : ValidationRule
{
public override ValidationResult Validate(object value, System.Globalization.CultureInfo cultureInfo)
{
var p = ((BindingGroup)value).Items[0] as Person;
if (p == null)
return ValidationResult.ValidResult;
if (string.IsNullOrEmpty(p.Name))
return new ValidationResult(false, "What, no name?");
return ValidationResult.ValidResult;
}
}
}
基本上,我的问题是,如果两者TestRule1
和 TestRule2 fail, I get an
ArgumentException bubbling up when I call
this.BindingGroup.ValidateWithoutUpdate() with message "Cannot have duplicates in this Collection", parameter name: "validationError". I dug around through the implementation of
BindingGroup , and it seems that it is using itself as the second parameter to
ValidationError , which is the
bindingInError parameter, which the underlying
ValidationErrorCollection` 需要是唯一的。
诚然,这个例子是人为的,但是,它完美地展示了我的现实世界问题,但事实并非如此。(我有 2 个完全独立ValidationRule
的 s,它们对同一业务对象的不同属性进行操作,将它们折叠成一个 s 是零意义的ValidationRule
)。此外,我能找到的每个示例BindingGroup
都只演示了单个 的使用ValidationRule
,但是该构造清楚地支持并接受多个规则,尽管显然,只要一次只有一个失败。
我是否做错了什么,或者这似乎是BindingGroup
实现中的一个错误,正如我目前倾向于认为的那样。
对于它的价值,我使用 VS2008 和 .Net 3.5 SP1。