Wpf 为什么IDataErrorInfo发射了多次?
我遇到了一个问题,Wpf 为什么IDataErrorInfo发射了多次?,wpf,silverlight,xaml,windows-phone-7,mvvm,Wpf,Silverlight,Xaml,Windows Phone 7,Mvvm,我遇到了一个问题,IDataErrorInfo多次被解雇 交易类别 public class Transaction : INotifyPropertyChanged, INotifyPropertyChanging, IDataErrorInfo { private Double? _transAmount; [Column(DbType = "decimal(19,4)")] public Double? TransAmount { get { return _transAmou
IDataErrorInfo
多次被解雇
交易类别
public class Transaction : INotifyPropertyChanged, INotifyPropertyChanging, IDataErrorInfo
{
private Double? _transAmount;
[Column(DbType = "decimal(19,4)")]
public Double? TransAmount
{
get { return _transAmount; }
set
{
if (_transAmount != value)
{
NotifyPropertyChanging("TransAmount");
_transAmount = value;
NotifyPropertyChanged("TransAmount");
}
}
}
#region INotifyPropertyChanged Members
public event PropertyChangedEventHandler PropertyChanged;
// Used to notify that a property changed
private void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
#endregion
#region INotifyPropertyChanging Members
public event PropertyChangingEventHandler PropertyChanging;
// Used to notify that a property is about to change
private void NotifyPropertyChanging(string propertyName)
{
if (PropertyChanging != null)
{
PropertyChanging(this, new PropertyChangingEventArgs(propertyName));
}
}
#endregion
#region Data Validation
public string Error { get { return null; } }
public string this[string property]
{
get
{
switch (property)
{
case "TransAmount":
if (TransAmount != null)
{
double value;
bool valid = double.TryParse(TransAmount.ToString(), out value);
if (!valid) { return TransAmount.ToString() + " is not a valid number"; }
else if (value <= 0) { return "Dollar amount must be greater than $0.00"; }
}
return null;
default:
return null;
}
}
}
#endregion
}
公共类事务:INotifyPropertyChanged、INotifyPropertyChanged、IDataErrorInfo
{
私家双卡;
[列(DbType=“十进制(19,4)”)]
公共双转载
{
获取{return\u transAmount;}
设置
{
如果(_transAmount!=值)
{
NotifyPropertyChange(“TransAmount”);
_交易量=价值;
NotifyPropertyChanged(“TransAmount”);
}
}
}
#区域INotifyProperty更改成员
公共事件属性更改事件处理程序属性更改;
//用于通知属性已更改
私有void NotifyPropertyChanged(字符串propertyName)
{
if(PropertyChanged!=null)
{
PropertyChanged(这是新的PropertyChangedEventArgs(propertyName));
}
}
#端区
#区域索引属性更改成员
公共事件属性更改EventHandler属性更改;
//用于通知属性即将更改
私有void notifyPropertyChangeg(字符串propertyName)
{
if(PropertyChange!=null)
{
PropertyChange(这是新的PropertyChangingEventArgs(propertyName));
}
}
#端区
#区域数据验证
公共字符串错误{get{return null;}}
公共字符串此[字符串属性]
{
得到
{
交换机(属性)
{
案例“TransAmount”:
if(TransAmount!=null)
{
双重价值;
bool valid=double.TryParse(TransAmount.ToString(),out值);
如果(!valid){return TransAmount.ToString()+“不是有效数字”;}
否则,如果(值则技巧如下
使用DataErrorValidationRule而不是ValidateSondaerRors=True
<TextBox>
<TextBox.Text>
<Binding Path="..." UpdateSourceTrigger="LostFocus" NotifyOnValidationError="True">
<Binding.ValidationRules>
<DataErrorValidationRule ValidatesOnTargetUpdated="False"/>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>
参考这篇文章它触发多少次都不重要。这会导致什么问题?实际上,WPF验证框架并不能“保证”整个“依赖性”框架只通过一次验证。请尝试改进验证代码,使之快速。@Bryant-这是WP7上的(只是添加了标记),我不确定如何向用户显示错误。为了查看错误,我在上面的文本框中添加了一个事件处理程序,BindingValidationError
。这将弹出一个消息框,显示IDataErrorInfo返回的错误内容。可能这是一个不正确的实现。@AngelWPF-您能详细说明一下吗?
<TextBox>
<TextBox.Text>
<Binding Path="..." UpdateSourceTrigger="LostFocus" NotifyOnValidationError="True">
<Binding.ValidationRules>
<DataErrorValidationRule ValidatesOnTargetUpdated="False"/>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>