Question

我正在尝试在代码隐藏中加载DataTemplate，但如果我删除转换器它可以正常工作......但是只要我把它放在那里，它就会被打破。现在，我确实设置了我的状态命名空间，并在XAML中放置了对我的转换器的引用。例如：

<Window.Resources>
     <local:StatCellConverter x:Key="myConverter" />
</Window.Resources>

这是我生成DataTemplate的方法：

private DataTemplate GenerateStatRowDataTemplate()
{
    ParserContext pc = new ParserContext();
    pc.XmlnsDictionary.Add("", "http://schemas.microsoft.com/winfx/2006/xaml/presentation");
    pc.XmlnsDictionary.Add("x", "http://schemas.microsoft.com/winfx/2006/xaml");
    pc.XmlnsDictionary.Add("xcdg", "http://schemas.xceed.com/wpf/xaml/datagrid");

    string statRowTemplate = "<DataTemplate><xcdg:StatRow>";
    statRowTemplate += "<xcdg:StatCell FieldName=\"Column4\" ResultPropertyName=\"AvgColumn4\">";
    statRowTemplate += "<xcdg:StatCell.ContentTemplate>";
    statRowTemplate += "<DataTemplate>";
    statRowTemplate += "<TextBlock Text=\"{Binding ., Converter={StaticResource ResourceKey=myConverter}}\" />";
    statRowTemplate += "</DataTemplate>";
    statRowTemplate += "</xcdg:StatCell.ContentTemplate>";
    statRowTemplate += "</xcdg:StatCell>";
    statRowTemplate += "</xcdg:StatRow>";
    statRowTemplate += "</DataTemplate>";

    StringReader stringReader = new StringReader(statRowTemplate);
    XmlReader xmlReader = XmlReader.Create(stringReader);
    MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(statRowTemplate.ToString()));
    DataTemplate dt = (DataTemplate)XamlReader.Load(ms,pc);
    dt.LoadContent();
    return dt;
}

我做错了什么？可能是我必须在后面的代码中定义我的转换器吗？

我的转换器

public class StatCellConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            Debug.WriteLine(value);

            if (value.Equals("#DIV/0#"))
                return "0";
            return value;
        }
        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }

我得到一个例外，说它无法加载DataTemplate

Answer 1

这实际上是框架中的一个错误。通过XmlnsDictionary添加本地名称空间将不起作用。必须在模板定义中添加它，并定义程序集和命名空间：

如上面的评论@Nerd In Training这应该有效：

string statRowTemplate = "<DataTemplate >"; 

private DataTemplate GenerateStatRowDataTemplate()
{
    ParserContext pc = new ParserContext();
    pc.XmlnsDictionary.Add("", "http://schemas.microsoft.com/winfx/2006/xaml/presentation");
    pc.XmlnsDictionary.Add("x", "http://schemas.microsoft.com/winfx/2006/xaml");
    pc.XmlnsDictionary.Add("xcdg", "http://schemas.xceed.com/wpf/xaml/datagrid");

    string statRowTemplate = "<DataTemplate xmlns:local=\"clr-namespace:MyTest;assembly=MyTest\" ><xcdg:StatRow>";
    statRowTemplate += "<xcdg:StatCell FieldName=\"Column4\" ResultPropertyName=\"AvgColumn4\">";
    statRowTemplate += "<xcdg:StatCell.ContentTemplate>";
    statRowTemplate += "<DataTemplate>";
    statRowTemplate += "<TextBlock Text=\"{Binding ., Converter={StaticResource ResourceKey=myConverter}}\" />";
    statRowTemplate += "</DataTemplate>";
    statRowTemplate += "</xcdg:StatCell.ContentTemplate>";
    statRowTemplate += "</xcdg:StatCell>";
    statRowTemplate += "</xcdg:StatRow>";
    statRowTemplate += "</DataTemplate>";

    StringReader stringReader = new StringReader(statRowTemplate);
    XmlReader xmlReader = XmlReader.Create(stringReader);
    MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(statRowTemplate.ToString()));
    DataTemplate dt = (DataTemplate)XamlReader.Load(ms,pc);
    dt.LoadContent();
    return dt;
}

Answer 2

完整版

    var ms = new MemoryStream(Encoding.UTF8.GetBytes(@"<DataTemplate xmlns=""http://schemas.microsoft.com/winfx/2006/xaml/presentation""
                                                                     xmlns:x=""http://schemas.microsoft.com/winfx/2006/xaml""                                                                             
                                                                     xmlns:c=""clr-namespace:MyApp.Converters;assembly=MyApp"">
            <DataTemplate.Resources>
                <c:MyConverter x:Key=""MyConverter""/>
            </DataTemplate.Resources>
            <TextBlock Text=""{Binding ., Converter={StaticResource MyConverter}}""/>
          </DataTemplate>"));
    var template = (DataTemplate)XamlReader.Load(ms);

    var cb = new ComboBox { };
    //Set the data template
    cb.ItemTemplate = template;

DataTemplate与代码背后的转换器

2 个答案: