从带有DataTemplateSelector的ResourceDictionary获取DataTemplate

public class MyDataTemplateSelector : DataTemplateSelector
{
    public override DataTemplate SelectTemplate(object item, DependencyObject container)
    {
        if (item is string)
        {
            return (DataTemplate)Application.Current.Resources["StringTemplate"];
        }
        else if (item is int)
        {
            return (DataTemplate)Application.Current.Resources["IntTemplate"];
        }
        // 其他条件和对应的DataTemplate
        // ...
        
        return null;
    }
}

<ResourceDictionary>
    <local:MyDataTemplateSelector x:Key="MyDataTemplateSelector" />
    
    <DataTemplate x:Key="StringTemplate">
        <!-- 字符串类型的数据模板 -->
        <!-- ... -->
    </DataTemplate>
    
    <DataTemplate x:Key="IntTemplate">
        <!-- 整数类型的数据模板 -->
        <!-- ... -->
    </DataTemplate>
    
    <!-- 其他类型的DataTemplate -->
    <!-- ... -->
</ResourceDictionary>

<ContentControl Content="{Binding MyData}" 
                ContentTemplateSelector="{StaticResource MyDataTemplateSelector}" />