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.
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}}")
<DataGridTemplateColumn Header="Verified" Width="150">
<DataGridTemplateColumn.CellTemplate>
<DataTemplate>
<Border Backgroun开发者_如何学Cd="{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?
Any help appreciated!
Converter looks roughly like this:
[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:
/// <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);
}
}
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.
Using a 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:
<Border.Background>
<MultiBinding Converter="{StaticResource convVerify}">
<Binding Value="{Binding TotalCount}" />
<Binding Value="{Binding NoOfVerified}" />
</MultiBinding>
</Border.Background>
Using Property Change Events
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");
}
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!!
[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)
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!!
<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>
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