绑定未使用DataTemplateSelector更新

Question

I have a WPF application based on MVVM. It has paramaters that can be set. A paramater can be a list of strings in a checkbox or a double in a numupdown. Every device has its own parameters, so the parameters are dynamically loaded. Thats why i use a DataTemplateSelector.

Xaml code

<ItemsControl ItemsSource="{Binding ParameterWrapperList}" ItemTemplateSelector="{StaticResource propertyDataTemplateSelector}">
    <ItemsControl.ItemsPanel>
      <ItemsPanelTemplate>
        <StackPanel Orientation="Horizontal"></StackPanel>
      </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
</ItemsControl>

The templates are in a resource dictionary:

  <DataTemplate x:Key="doubleTemplate"> <Grid Visibility="{Binding Parameter.ParameterModel.IsVisible, Converter={StaticResource Visibility}}"> <Grid.RowDefinitions> <RowDefinition Height="{Binding Path=RowHeight, Mode=OneWay}"/> <RowDefinition/> </Grid.RowDefinitions> <Border Grid.Row="0" Style="{StaticResource HeaderBorderStyle}" Width="{Binding Width}" Visibility="{Binding HeaderVisibility, Converter={StaticResource Visibility}}"> <StackPanel Orientation="Horizontal"> <Label Content="{Binding Parameter.DisplayName}"/> </StackPanel> </Border> <Border Grid.Row="1" Style="{StaticResource ItemBorderStyle}" Width="{Binding Width}"> <telerik:RadNumericUpDown Name="nudParameterValue" Value="{Binding Path=ParameterValue, Mode=TwoWay}" Minimum="{Binding Parameter.ParameterModel.MinimumValue}" Maximum="{Binding Parameter.ParameterModel.MaximumValue}" NumberDecimalDigits="{Binding Parameter.ParameterModel.NumberDecimalDigits}" SmallChange="{Binding Parameter.ParameterModel.SmallChanges}"/> </Border> </Grid> </DataTemplate> <DataTemplate x:Key="stringTemplate"> <Grid Visibility="{Binding Parameter.ParameterModel.IsVisible, Converter={StaticResource Visibility}}"> <Grid.RowDefinitions> <RowDefinition Height="{Binding Path=RowHeight, Mode=OneWay}"/> <RowDefinition/> </Grid.RowDefinitions> <Border Grid.Row="0" Style="{StaticResource HeaderBorderStyle}" Width="{Binding Width}" Visibility="{Binding Path=HeaderVisibility, Converter={StaticResource Visibility}}"> <Label Content="{Binding Parameter.DisplayName}"/> </Border> <Border Grid.Row="1" Style="{StaticResource ItemBorderStyle}" Width="{Binding Width}" > <ComboBox ItemsSource="{Binding Path=Parameter.ParameterModel.PossibleValues}" SelectedIndex="{Binding ParameterValue, Mode=TwoWay}"> </ComboBox> </Border> </Grid> </DataTemplate> <configControl:PropertyDataTemplateSelector StringTemplate="{StaticResource stringTemplate}" DoubleTemplate="{StaticResource doubleTemplate}" x:Key="propertyDataTemplateSelector"/> 

I wrote the code for the DataTemplateSelector.

    public class PropertyDataTemplateSelector : DataTemplateSelector
{
    public DataTemplate DoubleTemplate { get; set; }
    public DataTemplate StringTemplate { get; set; }

    public override DataTemplate SelectTemplate(object item,
               DependencyObject container)
    {
        DeviceModel.ParameterType devFunct = ((ParameterWrapper)item).Parameter.ParameterModel.Type;
        switch (devFunct)
        {
            case DeviceModel.ParameterType.Double:
                return DoubleTemplate;
            case DeviceModel.ParameterType.String:
                return StringTemplate;
            default:
                return null;
        }
        return null;            
    }
}

When the applications opens all the values are set fine. But when i update ParameterValue, it isn't updated on view. (when i output the values in console window, the values are set fine (but not in the GUI)).

What should i do to make this work.

Edit

This is the code it's bound to. Every function has a checkbox and when you change the parameter of one, all other parameters that are checked need to change.

        public double ParameterValue
    {
        get
        {
            return _parameter.ParameterValue;
        }
        set
        {
            Parameter.ParameterValue = value;
            Console.WriteLine("ParameterValueChanged");
            if (SetOthers)
            {
                if (_parentFunction.Checked)
                {
                    foreach (var function in _parentFunction.FunctionWrapperList)
                    {
                        if (function.Checked)
                        {
                            foreach (var parameterWrapper in function.ParameterWrapperList)
                            {
                                if (parameterWrapper.Parameter != this.Parameter)
                                {
                                    if (parameterWrapper.Parameter.ParameterModel == Parameter.ParameterModel)
                                    {
                                        Console.WriteLine(function.Function.Name + " " + function.Checked + " " + Parameter.ParameterValue);
                                        parameterWrapper.SetValue(Parameter.ParameterValue);
                                    }
                                }
                            }
                        }
                    }
                }
            }
            Notify("ParameterValue");
        }
    }

    private void SetValue(double parameterValue)
    {
        SetOthers = false;
        Parameter.ParameterValue = parameterValue;
        SetOthers = true;
    }

The boolean SetOthers is so he won't get a stackoverflow and keeps setting itself.

Answer 1

Your DataTemplateSelector won't update the DataTemplate rendering your data because a DataTemplateSelector doesn't trigger on a property change. It only choose a way to display a data according to its type (yourData.GetType()).

What you want is a trigger:

<ItemsControl ItemsSource="{Binding ParameterWrapperList}">
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <ContentControl Content="{Binding}">
                <ContentControl.Style>
                    <Style TargetType="{x:Type ContentControl}">
                        <Setter Property="ContentTemplate" Value="{StaticResource doubleTemplate}"/>
                        <Style.Triggers>
                            <DataTrigger Binding="{Binding Parameter.ParameterModel.Type}" Value="{x:Static local:DeviceModel.ParameterType.String}">
                                <Setter Property="ContentTemplate" Value="{StaticResource stringTemplate}"/>
                            </DataTrigger>
                        </Style.Triggers>
                    </Style>
                </ContentControl.Style>
            </ContentControl>
        </DataTemplate>
    </ItemsControl.ItemTemplate>
    <ItemsControl.ItemsPanel>
      <ItemsPanelTemplate>
        <StackPanel Orientation="Horizontal"/>
      </ItemsPanelTemplate>
    </ItemsControl.ItemsPanel>
</ItemsControl>