[英]Binding error on XmlDataProvider (cannot bind to non-XML object)
I have a problem on binding some controls to my XML. 我在将某些控件绑定到XML时遇到问题。
My application populates a TabControl at runtime, loading the XAML for the TAB with DataTemplateSelector: 我的应用程序在运行时填充TabControl,并使用DataTemplateSelector加载TAB的XAML:
class TemplateSelector : DataTemplateSelector
{
public override DataTemplate SelectTemplate(object item, DependencyObject container)
{
if (item != null)
{
string templateFile = string.Format("Templates/{0}",
Properties.Settings.Default.AppId + ".tmpl");
if (File.Exists(templateFile))
{
FileStream fs = new FileStream(templateFile, FileMode.Open);
DataTemplate template = XamlReader.Load(fs) as DataTemplate;
Tab tab = item as Tab;
XmlDataProvider xmlDataProvider = template.Resources["dataProvider"] as XmlDataProvider;
xmlDataProvider.XPath = tab.BridgeObj.XmlFilePath;
return template;
}
}
return null;
}
}
the XAML: XAML:
<DataTemplate
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:EurocomCPS;assembly=EurocomCPS">
<DataTemplate.Resources>
<local:StringToBoolConverter x:Key="StrToBoolConverter" />
<local:StringToIntConverter x:Key="StrToIntConverter" />
<XmlDataProvider x:Key="dataProvider" XPath="func/parametri/param/BLOCKS"/>
</DataTemplate.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="100" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Label Grid.Row="0" Grid.Column="0" Content="ITEM 1:"/>
<Label Grid.Row="1" Grid.Column="0" Content="ITEM 2:"/>
<Label Grid.Row="2" Grid.Column="0" Content="ITEM 3:"/>
<TextBox Name="TextBox1"
Grid.Row="0"
Grid.Column="1"
Text="{Binding XPath='//BLOCK[@id=1]/ITEMS/ITEM[@id=1]/@value'}" />
<CheckBox Grid.Row="1"
Grid.Column="1"
IsChecked="{Binding XPath='//BLOCK[@id=1]/ITEMS/ITEM[@id=2]/@value',
Converter={StaticResource StrToBoolConverter}}"/>
<CheckBox Grid.Row="2"
Grid.Column="1"
IsChecked="{Binding XPath='//BLOCK[@id=1]/ITEMS/ITEM[@id=3]/@value',
Converter={StaticResource StrToBoolConverter}}"/>
</Grid>
</DataTemplate>
Every page hold an XmlDataProvider which load the following xml file: 每个页面都有一个XmlDataProvider,它会加载以下xml文件:
<func id="A29086">
<parametri>
<param>
<BLOCKS max_count="2" write_id="49" read_req_id="47" read_rep_id="48" session_id="7">
<BLOCK id="1" frame="1" framelen="61">
<ITEMS max_count="14">
<ITEM id="1" type="CHAR" size="1" value="0" />
<ITEM id="2" type="CHAR" size="1" value="1" />
<ITEM id="3" type="CHAR" size="1" value="0" />
...
</ITEMS>
</BLOCK>
<BLOCK id="2" frame="1" framelen="61">
<ITEMS max_count="14">
<ITEM id="1" type="CHAR" size="1" value="0" />
<ITEM id="2" type="CHAR" size="1" value="1" />
...
</ITEMS>
</BLOCK>
</BLOCKS>
</param>
</parametri>
</func>
When running I get this error: 运行时出现此错误:
System.Windows.Data Error: 44 : BindingExpression with XPath cannot bind to non-XML object.; XPath='//BLOCK[@id=1]/ITEMS/ITEM[@id=1]/@value' BindingExpression:Path=/InnerText; DataItem='Tab' (HashCode=57706919); target element is 'TextBox' (Name=''); target property is 'Text' (type 'String') Tab:'EurocomCPS.Tab'
System.Windows.Data Error: 44 : BindingExpression with XPath cannot bind to non-XML object.; XPath='//BLOCK[@id=1]/ITEMS/ITEM[@id=2]/@value' BindingExpression:Path=/InnerText; DataItem='Tab' (HashCode=57706919); target element is 'CheckBox' (Name=''); target property is 'IsChecked' (type 'Nullable`1') Tab:'EurocomCPS.Tab'
System.Windows.Data Error: 44 : BindingExpression with XPath cannot bind to non-XML object.; XPath='//BLOCK[@id=1]/ITEMS/ITEM[@id=3]/@value' BindingExpression:Path=/InnerText; DataItem='Tab' (HashCode=57706919); target element is 'CheckBox' (Name=''); target property is 'IsChecked' (type 'Nullable`1') Tab:'EurocomCPS.Tab'
--- EDIT --- -编辑-
I add the DataContext to my controls but I still have problems. 我将DataContext添加到控件中,但是仍然有问题。
The first is that I get the following: 首先 ,我得到以下信息:
System.Windows.Data Error: 44 : BindingExpression with XPath cannot bind to non-XML object.; XPath='//BLOCK[@id=1]/ITEMS/ITEM[@id=1]/@value' BindingExpression:Path=/InnerText; DataItem='Tab' (HashCode=46144604); target element is 'TextBox' (Name=''); target property is 'Text' (type 'String') Tab:'EurocomCPS.Tab'
System.Windows.Data Error: 44 : BindingExpression with XPath cannot bind to non-XML object.; XPath='//BLOCK[@id=1]/ITEMS/ITEM[@id=1]/@value' BindingExpression:Path=/InnerText; DataItem='Tab' (HashCode=46144604); target element is 'TextBox' (Name='TextBox1'); target property is 'Text' (type 'String') Tab:'EurocomCPS.Tab'
And I don't understand what is the first 'unnamed' textbox which is not defined anywhere. 我不明白什么是第一个未命名的“未命名”文本框。
Second is that, if I put a converter to the TextBox binding (eg, like the one I use for the CheckBoxes) I don't get the error. 其次是,如果我将转换器与TextBox绑定(例如,与我用于CheckBox的转换器一样),则不会收到该错误。
Third the Converter functions are not called. 第三 ,不调用Converter函数。
我认为'@ id = 1'不是按照Blog的正确方法。
Assuming that you somehow load XML into XmlDataProvider
, as I don't see Source
defined anywhere, your XPath
is fine but you don't provide the Source
for your binding. 假设您以某种方式将XML加载到XmlDataProvider
,因为我在任何地方都没有看到Source
定义,那么您的XPath
很好,但是您没有为绑定提供Source
。 It should work if you change it to something like this: 如果将其更改为以下内容,它应该可以工作:
<TextBlock Text="{Binding Source={StaticResource dataProvider}, XPath='//BLOCK[@id=1]/ITEMS/ITEM[@id=2]/@value'}"/>
if you won't specify source by default it will look in DataContext
. 如果默认情况下不指定源,它将在DataContext
查找。
The problem was the method using to assign the XML file!! 问题是用于分配XML文件的方法!!
xmlDataProvider.XPath = tab.BridgeObj.XmlFilePath;
Changing it to 更改为
xmlDataProvider.Source = new Uri(tab.BridgeObj.XmlFilePath);
has solved. 解决了。
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