可以说我有一组这样的模型类：
public class Person
{
public string Name { get; set; }
public ObservableCollection<Job> Jobs { get; private set; }
}
public class Job
{
public string Title { get; set; }
public DateTime? Start { get; set; }
public DateTime? End { get; set; }
}
我像这样设置我的xaml来显示一个人的列表和一个视图的所有细节：
<StackPanel Orientation="Horizontal">
<ListView ItemsSource="{Binding}" Width="200" DisplayMemberPath="Name" IsSynchronizedWithCurrentItem="True" />
<DockPanel Width="200" Margin="10,0">
<TextBox Text="{Binding Name}" DockPanel.Dock="Top" Margin="0,0,0,10"/>
<ListView ItemsSource="{Binding Jobs}" Name="_jobList" DisplayMemberPath="Title" IsSynchronizedWithCurrentItem="True"/>
</DockPanel>
<StackPanel Width="200" DataContext="{Binding ElementName=_jobList, Path=SelectedItem}">
<TextBox Text="{Binding Title}"/>
<DatePicker SelectedDate="{Binding Start}"/>
<DatePicker SelectedDate="{Binding End}"/>
</StackPanel>
</StackPanel>
整个Window的DataContext是People的ObservbleCollection.这似乎运作得相当好.我现在想添加一些验证,我不知道从哪里开始.
我想验证作业字段,以便用户无法选择另一个作业(或人员),如果标题为空或同一个人内的副本,或者日期不按顺序.此外,如果名称为空,则无法更改Person.
我已经阅读了一些关于WPF验证的内容,但是没有找到任何明确的解决方案.做这样的事情的最佳做法是什么？
另外,我的绑定是否正如我在最后一个面板上设置DataContext那样？它有效,但感觉有点粗略.另一种方法是为CollectionDataSources声明资源,我也不能很容易地想出这个方法.
最佳答案 对于验证部分,您可以从这里开始：
http://codeblitz.wordpress.com/2009/05/08/wpf-validation-made-easy-with-idataerrorinfo/
理解了文章后,您可以像这样修改类：
例如,让我们为职位和工作开始日期添加非空标题验证：
工作类：
public class Job : IDataErrorInfo
{
public string Title { get; set; }
public DateTime? Start { get; set; }
public DateTime? End { get; set; }
public string Error
{
get { throw new NotImplementedException(); }
}
public string this[string columnName]
{
get
{
string result = null;
if (columnName == "Title")
{
if (string.IsNullOrEmpty(Title))
result = "Please enter a Title ";
}
if (columnName == "Start")
{
if (Start == null)
result = "Please enter a Start Date";
else if (Start > End)
{
result = "Start Date must be less than end date";
}
}
return result;
}
}
}
//////////假设我们使用一个名为MainWindow的窗口为你的xaml代码看起来像
MainWindow.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="MainWindow" Height="350" Width="525"
x:Name="mainWindow">
<Window.Resources>
<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>
</Window.Resources>
<Grid>
<StackPanel Orientation="Horizontal">
<ListView ItemsSource="{Binding}" Width="200" DisplayMemberPath="Name" IsSynchronizedWithCurrentItem="True" IsEnabled="{Binding ElementName=mainWindow, Path=FormHasNoNoErrors}"/>
<DockPanel Width="200" Margin="10,0">
<TextBox Text="{Binding Name}" DockPanel.Dock="Top" Margin="0,0,0,10"/>
<ListView ItemsSource="{Binding Jobs}" Name="_jobList" DisplayMemberPath="Title" IsSynchronizedWithCurrentItem="True" IsEnabled="{Binding ElementName=mainWindow, Path=FormHasNoNoErrors}" />
</DockPanel>
<StackPanel Width="200" DataContext="{Binding ElementName=_jobList, Path=SelectedItem}">
<TextBox Text="{Binding Title, ValidatesOnDataErrors=true, NotifyOnValidationError=true}" Validation.Error="Validation_OnError" Validation.ErrorTemplate="{StaticResource errorTemplate}"/>
<DatePicker SelectedDate="{Binding Start, ValidatesOnDataErrors=true, NotifyOnValidationError=true}" Validation.Error="Validation_OnError" Validation.ErrorTemplate="{StaticResource errorTemplate}"/>
<DatePicker SelectedDate="{Binding End}"/>
</StackPanel>
</StackPanel>
</Grid>
</Window>
////////MainWindow.xaml.cs
public partial class MainWindow : Window, INotifyPropertyChanged
{
public MainWindow()
{
var jobs1 = new ObservableCollection<Job>()
{
new Job() {Start = DateTime.Now, End = DateTime.Now.AddDays(1), Title = "Physical Enginer"},
new Job() {Start = DateTime.Now, End = DateTime.Now.AddDays(1), Title = "Mechanic"}
};
var jobs2 = new ObservableCollection<Job>()
{
new Job() {Start = DateTime.Now, End = DateTime.Now.AddDays(1), Title = "Doctor"},
new Job() {Start = DateTime.Now, End = DateTime.Now.AddDays(1), Title = "Programmer"}
};
var personList = new ObservableCollection<Person>()
{
new Person() {Name = "john", Jobs = jobs1},
new Person() {Name="alan", Jobs=jobs2}
};
this.DataContext = personList;
InitializeComponent();
}
private void Validation_OnError(object sender, ValidationErrorEventArgs e)
{
if (e.Action == ValidationErrorEventAction.Added)
NoOfErrorsOnScreen++;
else
NoOfErrorsOnScreen--;
}
public bool FormHasNoNoErrors
{
get { return _formHasNoErrors; }
set
{
if (_formHasNoErrors != value)
{
_formHasNoErrors = value;
PropertyChanged(this, new PropertyChangedEventArgs("FormHasNoErrors"));
}
}
}
public int NoOfErrorsOnScreen
{
get { return _noOfErrorsOnScreen; }
set
{
_noOfErrorsOnScreen = value;
FormHasNoNoErrors = _noOfErrorsOnScreen == 0 ? true : false;
}
}
private int _noOfErrorsOnScreen = 0;
private bool _formHasNoErrors = true;
public event PropertyChangedEventHandler PropertyChanged = delegate {};
}
//////////////////////
I would like to validate the Job
fields so that the user cannot select
another Job (or person) if the title
is empty or a duplicate within the
same person, or if the dates are out
of order. Additionally, the Person
cannot be changed if the name is
empty.
一个简单的解决方案是,如果表单有错误(这就是我在上面的代码中所做的那样),则禁用列表框,并在没有错误时启用它们.你也应该在它们上面放一个带有工具提示的漂亮红色边框,向用户解释为什么他不能再选择了.
为了验证标题是否在同一个人中是重复的,您可以将上面的验证机制扩展为具有接收Person的ValidationService类,并查看具有该作业的人是否还有另一个具有相同名称的人.
public class Person：IDataErrorInfo
{
public string this[string columnName]
{
get
{
//look inside person to see if it has two jobs with the same title
string result = ValidationService.GetPersonErrors(this);
return result;
}
...
}
Also, is my binding ok the way I set
the DataContext on the last panel like
that? It works, but it feels a little
sketchy. The alternative is declaring
resources for the
CollectionDataSources and I couldn’t
really figure that method out very
easily either.
它不是MVVM的精神,如果你所做的不仅仅是一个小测试项目,你应该尝试学习MVVM(你可以从这里开始：http://fernandomachadopirizen.wordpress.com/2010/06/10/a-simple-introduction-to-the-model-view-viewmodel-pattern-for-building-silverlight-and-windows-presentation-foundation-applications/)
然后你不会直接绑定到一个人列表,而是你会绑定一些MainWindowViewModel类.此MainWindowViewModel类将包含人员列表,您将绑定到该列表.
对于选择,您将在MainWindowViewModel中拥有一个CurrentJob属性,即当前选定的作业,您将绑定到该：
基本上是这样的：
<StackPanel Orientation="Horizontal">
<ListView ItemsSource="{Binding PersonList}" SelectedItem="{Binding CurrentPerson, Mode=TwoWay}" Width="200" DisplayMemberPath="Name" IsSynchronizedWithCurrentItem="True" IsEnabled="{Binding ElementName=mainWindow, Path=FormHasNoNoErrors}"/>
<DockPanel Width="200" Margin="10,0">
<TextBox Text="{Binding Name}" DockPanel.Dock="Top" Margin="0,0,0,10"/>
<ListView ItemsSource="{Binding Jobs}" SelectedItem="{Binding CurrentJob, Mode=TwoWay}", DisplayMemberPath="Title" IsSynchronizedWithCurrentItem="True" />
</DockPanel>
<StackPanel Width="200">
<TextBox Text="{Binding CurrentJob.Title}"/>
.....
</StackPanel>
</StackPanel>
和你的MainWindowViewModel：
public class MainWindowViewModel :
{
...
//Public Properties
public ObservableCollection<Person> PersonList ....
public Job CurrentJob ....
....
}
