我需要做什么,使ContentControl与IDataErrorInfo一起工作,并在选中或取消选中复选框时检查有效性？
一些代码：
捆绑：
<ContentControl Content="{Binding GeneralInvoiceTypes,ValidatesOnDataErrors=True}"
Margin="0,5,0" />
数据模板：
<DataTemplate DataType="{x:Type viewmodels:MultipleOptionsviewmodel}">
<GroupBox Header="{Binding Title}">
<ItemsControl ItemsSource="{Binding Options}" />
</GroupBox>
</DataTemplate>
<DataTemplate DataType="{x:Type viewmodels:Optionviewmodel}">
<CheckBox IsChecked="{Binding IsChecked}"
Content="{Binding Name}"
Margin="6,3,0" />
</DataTemplate>
样式：
<Style TargetType="{x:Type ContentControl}">
<Style.Triggers>
<Trigger Property="Validation.HasError"
Value="true">
<Setter Property="ToolTip"
Value="{Binding RelativeSource={x:Static RelativeSource.Self},Path=(Validation.Errors)[0].ErrorContent}" />
</Trigger>
</Style.Triggers>
<Setter Property="Validation.ErrorTemplate">
<Setter.Value>
<ControlTemplate>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="90*" />
<ColumnDefinition Width="20" />
</Grid.ColumnDefinitions>
<Border BorderBrush="Red"
BorderThickness="1"
CornerRadius="2.75"
Grid.Column="0">
<AdornedElementPlaceholder Grid.Column="0" />
</Border>
<TextBlock Foreground="Red"
Grid.Column="1"
Margin="0"
FontSize="12"
VerticalAlignment="Center"
HorizontalAlignment="Left"
x:Name="txtError">
*
</TextBlock>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
解决方法
What do I have to do,to make the ContentControl work together with
IDataErrorInfo and check the validity when a check Box is checked or
unchecked?
添加一点Rachels回答.
使用异步数据验证更容易解决此问题,但遗憾的是,这在WPF 4.5 is released之前不可用.
内容绑定到Mainviewmodel中的GeneralInvoiceTypes.由于我们不能进行异步数据验证,因此必须为GeneralInvoiceTypes引发PropertyChanged以进行验证.这可行,但我会采用Rachel建议的方法,并在MultipleOptionsviewmodel中引入另一个名为IsValid的属性
可以从Tag(或附加属性)到GeneralInvoiceTypes.IsValid完成对IsValid的绑定.当在任何选项中更改IsChecked时,我们还必须在MultipleOptionsviewmodel中得到通知.例如,可以通过在CheckBoxes中使用命令绑定来完成此操作.
因此,需要沿着以下几行进行一些更改.
我还上传了一个示例项目,在此实现：https://www.dropbox.com/s/fn8e4n4s68wj3vk/ContentControlValidationTest.zip?dl=0
ContentControl中
<ContentControl Content="{Binding Path=GeneralInvoiceTypes}"
Tag="{Binding Path=GeneralInvoiceTypes.IsValid,ValidatesOnDataErrors=True}" />
Optionviewmodel DataTemplate
<DataTemplate DataType="{x:Type viewmodels:Optionviewmodel}">
<CheckBox IsChecked="{Binding IsChecked}"
Content="{Binding Name}"
Command="{Binding RelativeSource={RelativeSource AncestorType={x:Type ContentControl}},Path=DataContext.IsValidCheckCommand}"
Margin="6,0" />
</DataTemplate>
MultipleOptionsviewmodel
private ICommand m_isValidCheckCommand;
public ICommand IsValidCheckCommand
{
get
{
return m_isValidCheckCommand ??
(m_isValidCheckCommand = new RelayCommand(param => IsValidCheck()));
}
}
private void IsValidCheck()
{
IsValid = CheckIsValid();
}
private bool CheckIsValid()
{
foreach (Optionviewmodel option in Options)
{
if (option.IsChecked == true)
{
return true;
}
}
return false;
}
private bool m_isValid;
public bool IsValid
{
get { return m_isValid; }
set
{
m_isValid = value;
OnPropertyChanged("IsValid");
}
}
public string this[string columnName]
{
get
{
if (columnName == "IsValid")
{
if (IsValid == false)
{
return "At least 1 Option must be selected";
}
}
return string.Empty;
}
}
