让Silverlight AutoCompleteBox控件支持多属性筛选
首先我们先建立一个实体类并创建它的集合用于绑定控件的ItemSource属性，这个实体类有两个属性，如下：
1: public class AUser
2: {
3: public string Name { set; get; }
4: public string Age { set; get; }
5: }
编写XAML如下：
<sdk:AutoCompleteBox Height="28" Name="autoCompleteBox1" ValueMemberPath="Age" >
<sdk:AutoCompleteBox.ItemTemplate>
<DataTemplate>
<StackPanel>
<TextBlock Text="{Binding Name}"/>
<TextBlock Text="{Binding Age}"/>
</StackPanel>
</DataTemplate>
</sdk:AutoCompleteBox.ItemTemplate>
</sdk:AutoCompleteBox>
大家都知道， 一般情况下AutoCompleteBox控件只能筛选绑定项中的一个属性，(及ValueMemberPath在本例中只能设置为Name或Age),并且ValueMemberPath属性中的路径既是筛选属性路径又是选定项的结果属性路径。
接下来我们扩展它，使它能支持多属性路径，并能指定输出结果属性路径。我的解决思路是利用附加属性的力量达到目标，代码如下：
1: public static class AutoCompleteBoxHelper
2: {
3: private static void OnIsOtherPathChanged(DependencyObject obj,
DependencyPropertyChangedEventArgs e)
4: {
5: var acb = obj as AutoCompleteBox;
6: if (!string.IsNullOrEmpty(e.NewValue.ToString()))
7: {
8: acb.ItemFilter = (s,item)=>{
9: var objType = item.GetType();
10: string path = GetOtherPaths(acb);
11: var pathes = path.Split(',');
12: bool result = false;
13: foreach (string p in pathes)
14: {
15: var propertyInfo = objType.GetProperty(p);
16: string value = propertyInfo.GetValue(item, null).ToString();
17: result |= value.Contains(s);
18: }
19: return result;
20: };
21: }
22: else
23: acb.ItemFilter = null;
24: }
25:
26: public static string GetOtherPaths(DependencyObject obj)
27: {
28: return (string)obj.GetValue(OtherPathsProperty);
29: }
30:
31: public static void SetOtherPaths(DependencyObject obj, string value)
32: {
33: obj.SetValue(OtherPathsProperty, value);
34: }
35:
36: public static readonly DependencyProperty OtherPathsProperty =
37: DependencyProperty.RegisterAttached("OtherPaths", typeof(string),
38: typeof(AutoCompleteBoxHelper),
39: new PropertyMetadata("", OnIsOtherPathChanged));
40: }
OtherPaths属性就是一个支持多属性路径的属性（如”Name,Age”），并且指定了OtherPaths后ValueMemeberPath的筛选作用就不再工作了，而只保留了选定结果项属性路径的功能。
最后要叫它工作：
<sdk:AutoCompleteBox Height="28" Name="autoCompleteBox1" ValueMemberPath="Age"
loc:AutoCompleteBoxHelper.OtherPaths="Age,Name">
运行结果:
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