从带有DataTemplateSelector的ResourceDictionary获取DataTemplate

Question

目前我正在使用DataTemplateSelector在我的UserControl.Resources中查找DataTemplates，但我想将它们移到ResourceDictionary中。如何从DataTemplateSelector中查看ResourceDictionary？

这是我目前的DataTemplateSelector：

    public class SettingsDataTemplateSelector : DataTemplateSelector
{
    public override DataTemplate SelectTemplate(object item, DependencyObject container)
    {
        FrameworkElement element = container as FrameworkElement;

        if (element != null && item != null && item is Setting)
        {
            Setting registeritem = item as Setting;

            if (registeritem.EditValueVar.EditType == EditType.Textfield)
                return element.FindResource("TextboxDataTemplate") as DataTemplate;
            else if (registeritem.EditValueVar.EditType == EditType.DropDown)
                return element.FindResource("ComboDataTemplate") as DataTemplate;
            else if (registeritem.EditValueVar.EditType == EditType.Slider)
                return element.FindResource("SliderDataTemplate") as DataTemplate;
            else
                throw new ArgumentOutOfRangeException(registeritem.EditValueVar.EditType.ToString());
        }

        return null;
    }
}

Answer 1

在单独的ResourceDictionary中定义DataTemplate，然后将其添加到App.xaml

<ResourceDictionary.MergedDictionaries>        
    <ResourceDictionary Source="Resources/MyDataTemplate.xaml" />
</ResourceDictionary.MergedDictionaries>

在您的DataTemplateSelector中，您可以通过以下方式获取模板：

Application.Current.FindResource("myCustomDataTemplate") as DataTemplate;

其中，myCustomDataTemplate是您在MyDataTemplate.xaml文件中指定的数据模板的键。

Answer 2

您可以向DataTemplateSelector类添加ResourceDictionary属性：

public class SettingsDataTemplateSelector : DataTemplateSelector
{
    public ResourceDictionary ResourceDictionary { get; set; }

    public override DataTemplate SelectTemplate(object item, DependencyObject container)
    {
        FrameworkElement element = container as FrameworkElement;
        if (element != null && item != null && item is Setting)
        {
            Setting registeritem = item as Setting;

            if (registeritem.EditValueVar.EditType == EditType.Textfield)
                return ResourceDictionary["TextboxDataTemplate"] as DataTemplate;
            else if (registeritem.EditValueVar.EditType == EditType.DropDown)
                return ResourceDictionary["ComboDataTemplate"] as DataTemplate;
            else if (registeritem.EditValueVar.EditType == EditType.Slider)
                return ResourceDictionary["SliderDataTemplate"] as DataTemplate;
            else
                throw new ArgumentOutOfRangeException(registeritem.EditValueVar.EditType.ToString());
        }

        return null;
    }
}

您在XAML中设置的...that：

<local:SettingsDataTemplateSelector x:Key="selector">
    <local:SettingsDataTemplateSelector.ResourceDictionary>
        <ResourceDictionary Source="Dictionary1.xaml" />
    </local:SettingsDataTemplateSelector.ResourceDictionary>
</local:SettingsDataTemplateSelector>