如何在绑定到模板中的整个对象时强制刷新绑定

I have a List of 'Rule' classes that is the source of a DataGrid. In this example I have one of the columns which is a DataGridTemplateColumn that is bound to the 'Verified' dependency property.

我有一个'Rule'类列表,它是DataGrid的源代码。在这个例子中,我有一个列是DataGridTemplateColumn,它绑定到'Verified'依赖项属性。

The problem I am having is that I have a VerifyColorConverter where I wish to pass in the ENTIRE 'Rule' object of the selected row so I can examine the Rule instance and return an appropriate brush. I do this in when setting the background of the Border (see code below - Background="{Binding Converter={StaticResource convVerify}}")

我遇到的问题是我有一个VerifyColorConverter,我希望传入所选行的ENTIRE'Rule'对象,这样我就可以检查Rule实例并返回一个合适的画笔。我在设置Border的背景时这样做(参见下面的代码 - Background =“{Binding Converter = {StaticResource convVerify}}”)

<DataGridTemplateColumn Header="Verified" Width="150">
<DataGridTemplateColumn.CellTemplate>
    <DataTemplate>
        <Border Background="{Binding Converter={StaticResource convVerify}}" 
                CornerRadius="4" Height="17" Margin="2,0,2,0" VerticalAlignment="Center" >
            <Grid>
                <TextBlock Foreground="Yellow" Text="{Binding Path=Verified, Mode=OneWay}" TextAlignment="Center" VerticalAlignment="Center" 
                        FontSize="11" FontWeight="Bold" />
            </Grid>
        </Border>
    </DataTemplate>
</DataGridTemplateColumn.CellTemplate>

This all works well when I set the source on the DataGrid but when the underlying 'Rule' object is altered the converter is not called upon so the brush stays the same. How can I force this to be updated when I alter some of the properties of the 'Rule' instance?

当我在DataGrid上设置源代码时,这一切都很有效,但是当底层的“Rule”对象被更改时,转换器不会被调用,因此刷子保持不变。当我更改“规则”实例的某些属性时,如何强制更新此更新?

Any help appreciated!

任何帮助赞赏!

Converter looks roughly like this:

转换器看起来大致如下:

    [ValueConversion(typeof(CRule), typeof(SolidColorBrush))]
public class VerifyColorConverter : IValueConverter
{
    #region IValueConverter Members

    public object Convert(object value, Type targetType,
        object parameter, System.Globalization.CultureInfo culture)
    {
        CRule rule = value as CRule;

        Color clr = Colors.Red;

        int count = 0;
        int verified = 0;

        if (rule != null)
        {
            count = rule.TotalCount;    
            verified = rule.NoOfVerified; 
        }

        if (count == 0) clr = Colors.Transparent;
        else if (verified == 0) clr = (Color)ColorConverter.ConvertFromString("#FFD12626");
        else if (verified < count) clr = (Color)ColorConverter.ConvertFromString("#FF905132");
        else clr = (Color)ColorConverter.ConvertFromString("#FF568D3F");

        SolidColorBrush brush = new SolidColorBrush(clr);
        return brush;
    }

    public object ConvertBack(object value, Type targetType,
        object parameter, System.Globalization.CultureInfo culture)
    {
        throw new NotImplementedException();
    }

    #endregion
}

EDIT

This is part of Rule class:

这是Rule类的一部分:

   /// <summary>
/// Compliance Restriction (Rule)
/// </summary>
public class Rule : BindElement
{
    public CMode Mode { get; private set; }
    public int RuleID { get; private set; }
    public string RuleDescription { get; private set; }

    private int _NoOfVerified = 0;
    private int _TotalCount = 0;

    public int NoOfVerified
    {
        get { return _NoOfVerified; }
        set { _NoOfVerified = value; RaiseChanged("Progress"); RaiseChanged("Verified"); }
    }

    public int TotalCount
    {
        get { return _TotalCount; }
        set { _TotalCount = value; RaiseChanged("Progress"); RaiseChanged("Verified"); }
    }

    public string Verified 
    {
        get 
        {
            if (TotalCount == 0) return "Nothing to verify";
            return string.Format("Verified {0} out of {1}", NoOfVerified, TotalCount); 
        }
    }

2 个解决方案

#1

You could try using a MultiValueConverter instead of a regular Converter, and pass it whatever Rule Properties you need, or you can raise a CollectionChanged event when a property on the Rule gets changed. I usually prefer not to do this since I don't know how this affects performance, but it's an option.

您可以尝试使用MultiValueConverter而不是常规Converter,并将其传递给您需要的任何规则属性,或者您可以在规则上的属性发生更改时引发CollectionChanged事件。我通常不喜欢这样做,因为我不知道这会如何影响性能,但它是一种选择。

Using a MultiConverter

使用MultiConverter

public object Convert(object[] values, Type targetType,
    object parameter, System.Globalization.CultureInfo culture)
{
    Color clr = Colors.Red;

    int count = 0;
    int verified = 0;

    if (values.Count >= 2
        && int.TryParse(count, values[0].ToString()) 
        && int.TryParse(verfieid, values[1].ToString()))
    {
        if (count == 0) clr = Colors.Transparent;
        else if (verified == 0) clr = (Color)ColorConverter.ConvertFromString("#FFD12626");
        else if (verified < count) clr = (Color)ColorConverter.ConvertFromString("#FF905132");
        else clr = (Color)ColorConverter.ConvertFromString("#FF568D3F");
    }

    SolidColorBrush brush = new SolidColorBrush(clr);
    return brush;
}

XAML for MultiConverter:

XAML for MultiConverter:

<Border.Background>
    <MultiBinding Converter="{StaticResource convVerify}">
        <Binding Value="{Binding TotalCount}" />
        <Binding Value="{Binding NoOfVerified}" />
    </MultiBinding>
</Border.Background>

Using Property Change Events

使用属性更改事件

RulesCollection.CollectionChanged += RulesCollection_Changed;

void RulesCollection_Changed(object sender, CollectionChangedEventArgs e)
{
    if (e.NewItems != null)
        foreach(Rule rule in e.NewItems) // May need a cast here
            rule.PropertyChanged += Rule_PropertyChanged;

    if (e.OldItems != null)
        foreach(Rule rule in e.OldItems) // May need a cast here
            rule.PropertyChanged -= Rule_PropertyChanged;
}

void Rule_PropertyChanged()
{
    RaisePropertyChanged("RulesCollection");
}

#2

OK - I found a way around this - what I have done is expose the object as a property and then call the OnPropertyChanged for this property whenever anything changes. This is picked up properly by the Bind object and handed over to the Converter whenever a property changes!!

好的 - 我找到了解决这个问题的方法 - 我所做的是将对象公开为属性,然后在发生任何变化时为此属性调用OnPropertyChanged。这是由Bind对象正确拾取并在属性发生变化时移交给转换器!

    [Serializable()]
public class BindElement : INotifyPropertyChanged
{
    #region INotifyPropertyChanged Members

    [field: NonSerialized]
    public event PropertyChangedEventHandler PropertyChanged;

    public void OnPropertyChanged(PropertyChangedEventArgs e)
    {
        if (PropertyChanged != null)
            PropertyChanged(this, e);
    }

    public void RaiseChanged(string s)
    {
        OnPropertyChanged(new PropertyChangedEventArgs(s));
    }

    #endregion
}

public class BindElement2 : BindElement
{
    public void RaiseChanged(string s)
    {
        base.RaiseChanged(s);
        NudgeMyself();
    }

    public void NudgeMyself()
    {
        base.RaiseChanged("Myself");
    }
}

   /// <summary>
/// Compliance Restriction (Rule)
/// </summary>
public class CRule : BindElement2
{
    public CMode Mode { get; private set; }
    public int RuleID { get; private set; }
    public string RuleDescription { get; private set; }

    private int _NoOfVerified = 0;
    private int _TotalCount = 0;

    public int NoOfVerified
    {
        get { return _NoOfVerified; }
        set { _NoOfVerified = value; RaiseChanged("Progress"); RaiseChanged("Verified"); }
    }

    public int TotalCount
    {
        get { return _TotalCount; }
        set { _TotalCount = value; RaiseChanged("Progress"); RaiseChanged("Verified"); }
    }

    public string Verified 
    {
        get 
        {
            if (TotalCount == 0) return "Nothing to verify";
            return string.Format("Verified {0} out of {1}", NoOfVerified, TotalCount); 
        }
    }

    public CRule Myself
    {
        get { return this; }
    }

and other classes can derived from BindElement2 and do the same: (create a property Myself that exposes the instance itself)

和其他类可以从BindElement2派生并执行相同的操作:(创建一个公开实例本身的属性Myself)

    public class CTradeRule : BindElement2
{
    public CRule Rule { get; set; }
    public bool IsLocked { get; set; }      // if true this should prevent a Reason from being given
    public bool IsVerified { get { return Reason.Length > 0; } }

    private string _Reason = "";        // ** no reason **
    public string Reason 
    {
        get { return _Reason; }
        set { _Reason = value; RaiseChanged("Reason"); }
    }

    public int Progress
    {
        get { return (IsVerified ? 1 : 0); }
    }

    public override string ToString()
    {
        return string.Format("Rule: {0}, Reason: {1}", Rule.RuleID, _Reason);
    }

    public CTradeRule Myself
    {
        get { return this; }
    }
}

Now in the xaml I can do this: (note the Binding Path=Myself) which then ensures the entire object is send to the converter WHENEVER any property changes!!

现在在xaml中我可以这样做:(注意绑定路径=我自己)然后确保整个对象发送到转换器WHENEVER任何属性更改!

<DataGridTemplateColumn Header="Verified" Width="150">
<DataGridTemplateColumn.CellTemplate>
    <DataTemplate>
        <Border Background="{Binding Path=Myself, Converter={StaticResource convVerify}}" 
                CornerRadius="4" Height="17" Margin="2,0,2,0" VerticalAlignment="Center" >
            <Grid>
                <TextBlock Foreground="Yellow" Text="{Binding Path=Verified, Mode=OneWay}" TextAlignment="Center" VerticalAlignment="Center" 
                        FontSize="11" FontWeight="Bold" />
            </Grid>
        </Border>
    </DataTemplate>
</DataGridTemplateColumn.CellTemplate>