iphone - Monotouch.Dialog:启用ScopeBar时自动搜索被禁用

当我启用 ScopeBar 并在 Monotouch.Dialog 控件上连接 SelectedScopeButtonIndexChanged 时，将禁用在设置 EnabledSearch = true时启用的自动搜索功能。

禁用它的方法如下:

     UISearchBar sb = SearchBar;
     if (sb != null)
     {
        sb.ScopeButtonTitles = new string[] { "Girl".t(),"Boy".t(),"All".t() };
        sb.ShowsScopeBar = true;
        sb.SizeToFit();
        // THIS NEXT LINE KILLS SEARCH, remove to make it all work again
        sb.SelectedScopeButtonIndexChanged+= (sender, e) => {Update();};
     }

最佳答案

之所以中断搜索，是因为DialogViewController在UISearchBar上分配了一个自定义UISearchBarDelegate。

当您连接到事件时，它将取代Delegate并将其替换为特殊的UISearchBarDelegate，该UISearchBarDelegate将所有委托方法转发给事件。

换句话说，您不能在同一控件上将委托与事件混合和匹配。

一种可能的解决方案(如果您不想修补MonoTouch.Dialog本身)，是用您自己的自定义UISearchBarDelegate替换现有的sb.Delegate，该自定义UISearchBarDelegate可以实现SearchScope方法并将其他所有内容转发到先前已经设置的UISearchBarDelegate。

例如:

public class MySearchBarDelegate : UISearchBarDelegate
{
    UISearchBarDelegate original;
    MyDialogViewController dvc;

    public MySearchBarDelegate (MyDialogViewController dvc, UISearchBarDelegate original)
    {
        this.original = original;
    }

    public override void SelectedScopeButtonIndexChanged (UISearchBar searchBar, int selectedScope)
    {
        dvc.Update ();
    }

    public override void OnEditingStarted (UISearchBar searchBar)
    {
        original.OnEditingStarted (searchBar);
    }

    public override void OnEditingStopped (UISearchBar searchBar)
    {
        original.OnEditingStopped (searchBar);
    }

    public override void TextChanged (UISearchBar searchBar, string searchText)
    {
        original.TextChanged (searchBar, searchText);
    }

    public override void CancelButtonClicked (UISearchBar searchBar)
    {
        original.CancelButtonClicked (searchBar);
    }

    public override void SearchButtonClicked (UISearchBar searchBar)
    {
        original.SearchButtonClicked (searchBar);
    }
}