动态的DataTemplate与valueconverter [英] dynamic datatemplate with valueconverter

问题描述

我想在wpftoolkit数据网格，其中的数据是

I want to show data in a wpftoolkit datagrid where the data is a collection of

public class Thing
{
    public string Foo { get; set; }
    public string Bar { get; set; }
    public List<Candidate> Candidates { get; set; }
}

public class Candidate
{

    public string Name { get; set; }
    public CandidateType CandidateType { get; set; }
}

public enum CandidateType
{
    Type1,
    Type2,
    Type42
}

在哪里候选人名单的候选人数目在运行时配置。

where the number of candidates in Candidates list is configurable at runtime.

所需的网格布局看起来像这样

Desired grid layout looks like this

美孚|酒吧|候选人1 |候选2 | ... |候选ñ

这样看来，我不能创建在XAML考生的绑定表达式会改变一个DataTemplate。

Thus it seems I cannot create a DataTemplate for the candidates in xaml as the binding expression will change.

我在AutoGeneratedColumns事件中添加必要的列，像这样：

I add necessary columns in AutoGeneratedColumns event like so:

private void DataGrid_AutoGeneratedColumns(object sender, EventArgs e)
{
    ViewModel vm = DataContext as ViewModel;

    for (int i = 0; i < vm.LotsOfThings.First().Candidates.Count; i++)
    {
        string assName = Assembly.GetExecutingAssembly().GetName().Name;
        ParserContext ctx = new ParserContext();
        ctx.XamlTypeMapper = new XamlTypeMapper(new string[] { assName });
        ctx.XamlTypeMapper.AddMappingProcessingInstruction("src", "WpfToolkitDataGridTester", assName);
        ctx.XmlnsDictionary.Add("", "http://schemas.microsoft.com/winfx/2006/xaml/presentation");
        ctx.XmlnsDictionary.Add("x", "http://schemas.microsoft.com/winfx/2006/xaml");
        ctx.XmlnsDictionary.Add("src", "clr-namespace:WpfToolkitDataGridTester;assembly=" + assName);
        var template = XamlReader.Parse(@"<DataTemplate>
                                            <DataTemplate.Resources>
                                                <src:FooConverter x:Key='fooConverter' />
                                            </DataTemplate.Resources>
                                            <TextBlock  
                                                Foreground='{Binding Candidates[" + i + @"].CandidateType,Converter={StaticResource fooConverter}}'
                                                Text='{Binding Candidates[" + i + @"].Name}' />
                                        </DataTemplate>", ctx) as DataTemplate;
        dg.Columns.Add(new DataGridTemplateColumn
        {
            Header = "Candidate " + (i + 1),
            CellTemplate = template
        });
    }
}

然而，这失败，但以下情况除外：
上的标签'FooConverter'不存在XML命名空间存在'CLR命名空间：WpfToolkitDataGridTester;装配= WpfToolkitDataGridTester。行'3'位'54'。

This however fails with the following exception: The tag 'FooConverter' does not exist in XML namespace 'clr-namespace:WpfToolkitDataGridTester;assembly=WpfToolkitDataGridTester'. Line '3' Position '54'.

更改的StaticResource到DynamicResource不作任何改变。

Changing the StaticResource to DynamicResource makes no change.

我是什么？我缺少

FWIW：硬编码的DataTemplate

FWIW: a hardcoded datatemplate

<DataTemplate x:Key="candidateTemplate">
  <DataTemplate.Resources>
    <src:FooConverter x:Key="fooConverter" />
  </DataTemplate.Resources>
  <TextBlock 
    Foreground="{Binding Candidates[0].CandidateType,Converter={StaticResource fooConverter}}"
    Text="{Binding Candidates[0].Name}" />
</DataTemplate>

和像这样

<wpftk:DataGridTemplateColumn CellTemplate="{StaticResource candidateTemplate}" />

作品，但显然不会产生期望的结果为考生[0]是固定的。

'works' but obviously does not produce the desired result as Candidates[0] is hardcoded.

推荐答案

无论出于何种原因，它按预期工作，如果我做这样的...

For whatever reason, it works as expected if I do like this...

    string assName = Assembly.GetExecutingAssembly().GetName().Name;
    StringBuilder sb = new StringBuilder();
    sb.Append("<DataTemplate ");
    sb.Append("xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' ");
    sb.Append("xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml' ");
    sb.Append("xmlns:src='clr-namespace:WpfToolkitDataGridTester;assembly=" + assName + "' >");
    sb.Append("<DataTemplate.Resources>");
    sb.Append("<src:FooConverter x:Key='fooConverter' />");
    sb.Append("</DataTemplate.Resources>");
    sb.Append("<TextBlock ");
    sb.Append("Foreground='{Binding Candidates[" + i + "].CandidateType,Converter={StaticResource fooConverter}}' ");
    sb.Append("Text='{Binding Candidates[" + i + @"].Name}' />");
    sb.Append("</DataTemplate>");
    var template = (DataTemplate)XamlReader.Parse(sb.ToString());

这篇关于动态的DataTemplate与valueconverter的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！