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: