WPF数据验证之BindingGroup

BindingGroup 类  

             包含用于验证对象绑定和 ValidationRule 对象的集合。 

  主要用到的函数: BeginEdit()  开始在源中编辑事务在 BindingGroup。

                        CancelEdit()  关闭编辑事务并放弃挂起的更改。

                       主要原理（个人理解，可能有偏差）：通过BeginEdit()开启一个事务，提交数据之后，挂起更改，获取当前的数据，并对其内容进行验证，若通过验证，则提交事务；若失败则调用CancelEdit() 关闭编辑事务并放弃挂起的更改。

                      用途：在提交数据或者登录时，需要对多项数据进行验证时，可以考虑用BindingGroup；

<Window x:Class="WpfApplication_BingGroup.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:WpfApplication_BingGroup"
Title="BindingGroup" Height="247" Width="351">
<Grid>
<StackPanel Name="stackPanel1" >
<StackPanel.BindingGroup>
<BindingGroup NotifyOnValidationError="True">
<BindingGroup.ValidationRules>
<local:Validatess ValidationStep="ConvertedProposedValue"></local:Validatess>
</BindingGroup.ValidationRules>
</BindingGroup>
</StackPanel.BindingGroup>
<TextBox Height="23" Name="textBox1" Text="{Binding UserName, UpdateSourceTrigger=LostFocus}" Width="120" Margin="0,30,0,0" />
<TextBox Height="23" Name="textBox2" Text="{Binding PassWord, UpdateSourceTrigger=LostFocus}" Width="120" Margin="0,20,0,0" />
<StackPanel Height="37" Name="stackPanel2" Width="165" Margin="0,20,0,0" Orientation="Horizontal">
<Button Content="提交" Height="23" Name="button1" Width="60" Margin="10,0,0,0" Click="button1_Click" />
<Button Content="取消" Height="23" Name="button2" Width="60" Margin="20,0,0,0" Click="button2_Click" />
</StackPanel>
</StackPanel>
</Grid>
</Window>

 

 

/// <summary>
/// MainWindow.xaml 的交互逻辑
/// </summary>
public partial class MainWindow : Window
{
public MainWindow()
{
InitializeComponent();
//绑定数据源
this.stackPanel1.DataContext = new UserInfo();
//开启一个事务
this.stackPanel1.BindingGroup.BeginEdit();
}

private void button1_Click(object sender, RoutedEventArgs e)
{
if (this.stackPanel1.BindingGroup.CommitEdit())
{
MessageBox.Show("提交成功");
this.stackPanel1.BindingGroup.BeginEdit();
}
MessageBox.Show("提交失败");
}

private void button2_Click(object sender, RoutedEventArgs e)
{
//取消该事务
this.stackPanel1.BindingGroup.CancelEdit();
//重新启动一个事务
this.stackPanel1.BindingGroup.BeginEdit();
}

 

}

public class Validatess : ValidationRule
{
public override ValidationResult Validate(object value, CultureInfo cultureInfo)
{
//获取对象
BindingGroup bg = value as BindingGroup;
UserInfo ui = bg.Items[0] as UserInfo;

//验证条件，此处判断字符串的长度是否大于5
if(ui.UserName.Length>5&&ui.PassWord.Length>5)
{
return new ValidationResult(true,null);
}
return new ValidationResult(false,"验证错误");
}

}

public class UserInfo:INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private string userName;

public string UserName
{
get { return userName; }
set { userName = value;
PropertyChanged(this, new PropertyChangedEventArgs("UserName"));
}
}
private string passWord;

public string PassWord
{
get { return passWord; }
set { passWord = value;
PropertyChanged(this, new PropertyChangedEventArgs("PassWord"));
}
}
}