WPF ICollectionView过滤 [英] WPF ICollectionView Filtering

问题描述

我已经在ComboBox中为过滤项目编写了一个代码： 我的问题是，你会怎么做？

>

我认为这个反射的解决方案可能非常慢。

  ICollectionView view = CollectionViewSource.GetDefaultView（newValue）; 
 view.Filter + = this.FilterPredicate; 
 
 $ b private bool FilterPredicate（object value）
 {
 if（value == null）
 return false; 
 
 if（String.IsNullOrEmpty（SearchedText））
 return true; 
 $ b $ int index = value.ToString（）。IndexOf（
 SearchedText，
 0，
 StringComparison.InvariantCultureIgnoreCase）; 
 
 if（index> -1）返回true; 
 
返回FindInProperties（新字符串[] {Property1，Property2}，值，SearchedText）; 
 
 $ b $ private bool FindInProperties（string []属性，对象值，字符串txtToFind）
 {
 PropertyInfo info = null; 
 for（int i = 0; i< properties.Length; i ++）
 {
 info = value.GetType（）。GetProperty（properties [i]）; 
 if（info == null）continue; 
 
 object s = info.GetValue（value，null）; 
 if（s == null）continue; 
 $ b $ int index = s.ToString（）。IndexOf（
 txtToFind，
 0，
 StringComparison.InvariantCultureIgnoreCase）; 
 
 if（index> -1）返回true; 
} 
返回false; 
 
  

解决方案

/ p>

  ICollectionView view = CollectionViewSource.GetDefaultView（newValue）; 
 IEqualityComparer< String> comparer = StringComparer.InvariantCultureIgnoreCase; 
 view.Filter = o => {
 Person p = o as Person; 
返回p.FirstName.Contains（SearchedText，comparer）
 || p.LastName.Contains（SearchedText，comparer）; 
 
 
 
 $ b你需要动态地搜索属性吗？
I've written a code for filtering items in ComboBox:

My question is, how would you do that?

I think that this solution with reflection could be very slow..
ICollectionView view = CollectionViewSource.GetDefaultView(newValue);
view.Filter += this.FilterPredicate;


private bool FilterPredicate(object value)
{            
    if (value == null)
        return false;

    if (String.IsNullOrEmpty(SearchedText))
        return true;            

    int index = value.ToString().IndexOf(
        SearchedText,
        0,
        StringComparison.InvariantCultureIgnoreCase);

    if ( index > -1) return true;

    return FindInProperties(new string[] { "Property1", "Property2" }, value, SearchedText);
}

private bool FindInProperties(string[] properties, object value, string txtToFind)
{
    PropertyInfo info = null;
    for (int i = 0; i < properties.Length; i++)
    {
        info = value.GetType().GetProperty(properties[i]);
        if (info == null) continue;

        object s  = info.GetValue(value, null);
        if (s == null) continue;

        int index = s.ToString().IndexOf(
            txtToFind,
            0,
            StringComparison.InvariantCultureIgnoreCase);

        if (index > -1) return true;
    }
    return false;
}

解决方案
Why not just this:
ICollectionView view = CollectionViewSource.GetDefaultView(newValue);
IEqualityComparer<String> comparer = StringComparer.InvariantCultureIgnoreCase;
view.Filter = o => { 
                     Person p = o as Person; 
                     return p.FirstName.Contains(SearchedText, comparer) 
                            || p.LastName.Contains(SearchedText, comparer); 
                   }
Do you need to search properties dynamically?

                        
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