Silverlight中的AutococteTebox和InotifyDataErrorinfo
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26-10-2019 - |
题
是否有人成功地应用了InotifyDataErrorInfo接口并绑定到AutoCompleteBox。我已经尝试过,但是我没有回应。该控件不会响应其他控制,即用红色边框和警告工具提示。它还不会使验证摘要控制显示具有错误。
我已经成功设置了标准的文本框和datePitlers,并且按照互联网上人们提供的许多示例的表现非常完美。
如果我的屏幕一致性有一个答案,那将是很好的,这也是因为我想简单地绑定到InotifyDataErrorinfo随附的haserrors属性,以便在准备保存时启用一个按钮额外的代码以检查这些框是否正确。
目前,我通过使用MVVMlight Eventtocommand绑定并注册LostFocus事件的方式对待这些。
<sdk:AutoCompleteBox x:Name="TransferTypeTextBox" SelectedItem="{Binding Path=SelectedTransferType, Mode=TwoWay, ValidatesOnNotifyDataErrors=True, NotifyOnValidationError=True}" ItemsSource="{Binding Path=TransferTypes}" IsTextCompletionEnabled="True" Grid.Row="1" Grid.Column="1" Margin="0,3" Width="238" HorizontalAlignment="Left" FontFamily="/PtrInput_Silverlight;component/Fonts/Fonts.zip#Calibri" FontSize="13.333">
<i:Interaction.Triggers>
<i:EventTrigger EventName="LostFocus">
<cmd:EventToCommand Command="{Binding TransferTypeLostFocusCommand}" PassEventArgsToCommand="True"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</sdk:AutoCompleteBox>
然后,在ViewModel中,我将RoutedEventArgs.originalSource施加到文本框上,然后将文本放在这样,以防止用户离开盒子,除非它是空的或匹配盒子列表中的项目: -
private void OnTransferTypeLostFocus(RoutedEventArgs e)
{
System.Windows.Controls.TextBox box = (System.Windows.Controls.TextBox)e.OriginalSource;
// If user inputs text but doesn't select one item, show message.
if (this.Ptr.TransferType == null && !string.IsNullOrEmpty(box.Text))
{
MessageBox.Show("That is not a valid entry for Transfer Type", "Transfer type", MessageBoxButton.OK);
box.Focus();
}
}
解决方案
我试图尽我所能写作。我的模型观察属性搜索文本的更改和更新验证属性。
public class MainViewModel : INotifyPropertyChanged, INotifyDataErrorInfo
{
private Dictionary<string, List<string>> ErrorMessages = new Dictionary<string, List<string>>();
public MainViewModel()
{
//Validation works automatically for all properties that notify about the changes
this.PropertyChanged += new PropertyChangedEventHandler(ValidateChangedProperty);
}
//Validate and call 'OnErrorChanged' for reflecting the changes in UI
private void ValidateChangedProperty(object sender, PropertyChangedEventArgs e)
{
if (e.PropertyName == "HasErrors") //avoid recursion
return;
this.ValidateProperty(e.PropertyName);
OnErrorsChanged(e.PropertyName);
OnPropertyChanged("HasErrors");
}
//Just compare a received value with a correct value, it's a simple rule for demonstration
public void ValidateProperty(string propertyName)
{
if (propertyName == "SearchText")
{
this.ErrorMessages.Remove(propertyName);
if (SearchText != "Correct value")
this.ErrorMessages.Add("SearchText", new List<string> { "Enter a correct value" });
}
}
private string searchText;
public string SearchText
{
get { return searchText; }
set
{
searchText = value;
OnPropertyChanged("SearchText");
}
}
#region INotifyDataErrorInfo
public IEnumerable GetErrors(string propertyName)
{
return this.ErrorMessages.Where(er => er.Key == propertyName).SelectMany(er => er.Value);
}
public bool HasErrors
{
get { return this.ErrorMessages.Count > 0; }
}
public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged = delegate { };
private void OnErrorsChanged(string propertyName)
{
ErrorsChanged(this, new DataErrorsChangedEventArgs(propertyName));
}
#endregion
public event PropertyChangedEventHandler PropertyChanged = delegate { };
protected virtual void OnPropertyChanged(string propertyName)
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
和XAML:
<sdk:AutoCompleteBox Text="{Binding SearchText, Mode=TwoWay}" />
<Button IsEnabled="{Binding HasErrors, Converter={StaticResource NotConverter}}" Content="Save"/>
控件具有红色边框,并在模型有错误时禁用按钮。
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