如何设置 Gtk# TreeModelFilter 来过滤底层 TreeStore？

Question

我已阅读 "GtkSharp TreeView 教程"，其中作者描述了如何设置和使用 TreeModelFilter对于底层 ListStore（在教程“过滤数据”部分下）。该技术似乎不适用于底层分层 TreeStore。我想过滤多级 TreeStore 并在 TreeView 中显示结果。这让我很难过。有任何教程、示例或建议吗？

以下是代码。它与教程的代码基本相同，除了处理 TreeStore 而不是 ListStore 的构造和填充的更改之外。 {TreeStore 用于保存联系人的“姓名”和“电子邮件地址”，分为（并保存为）根“朋友”和“亲戚”的子级}

// compilation requires references to:
// gtk-sharp, atk-sharp and glib-sharp


using System;
using Gtk;

public class TreeViewExample
{
    public static void Main()
    {
        Gtk.Application.Init();
        new TreeViewExample();
        Gtk.Application.Run();
    }

    Gtk.Entry filterEntry;
    Gtk.TreeModelFilter filter;

    public TreeViewExample()
    {
        // Create a Window
        Gtk.Window window = new Gtk.Window("TreeView Example");
        window.SetSizeRequest(500, 200);
        window.DeleteEvent += delegate { Application.Quit(); };

        // Create an Entry used to filter the tree
        filterEntry = new Gtk.Entry();

        // Fire off an event when the text in the Entry changes
        filterEntry.Changed += OnFilterEntryTextChanged;

        // Create a nice label describing the Entry
        Gtk.Label filterLabel = new Gtk.Label("Search:");

        // Put them both into a little box so they show up side by side
        Gtk.HBox filterBox = new Gtk.HBox();
        filterBox.PackStart(filterLabel, false, false, 5);
        filterBox.PackStart(filterEntry, true, true, 5);

        // Create our TreeView
        Gtk.TreeView tv = new Gtk.TreeView();

        // Create a box to hold the Entry and Tree
        Gtk.VBox box = new Gtk.VBox();

        // Add the widgets to the box
        box.PackStart(filterBox, false, false, 5);
        box.PackStart(tv, true, true, 5);
        window.Add(box);

        //setting up columns and renderers
        Gtk.TreeViewColumn nameColumn = new Gtk.TreeViewColumn { Title = "Name" };
        Gtk.CellRendererText nameCell = new Gtk.CellRendererText();
        nameColumn.PackStart(nameCell, true);
        Gtk.TreeViewColumn emailColumn = new Gtk.TreeViewColumn { Title = "Email" };
        Gtk.CellRendererText emailCell = new Gtk.CellRendererText();
        emailColumn.PackStart(emailCell, true);

        // Add the columns to the TreeView
        tv.AppendColumn(nameColumn);
        tv.AppendColumn(emailColumn);

        // Tell the Cell Renderers which items in the model to display
        nameColumn.AddAttribute(nameCell, "text", 0);
        emailColumn.AddAttribute(emailCell, "text", 1);

        // Create a model that will hold two strings 
        Gtk.TreeStore contacts = new Gtk.TreeStore(typeof(string), typeof(string));

        // Add some hierarchical data
        Gtk.TreeIter treeiter;

        //first root
        treeiter = contacts.AppendValues("FRIENDS");

        // 2 children of first root
        contacts.AppendValues(treeiter, "Ogre", "[email protected]");
        contacts.AppendValues(treeiter, "Bee", "[email protected]");

        // second root
        treeiter = contacts.AppendValues("RELATIVES");

        // 3 children of second root
        contacts.AppendValues(treeiter, "Mommy", "[email protected]");
        contacts.AppendValues(treeiter, "Daddy", "[email protected]");
        contacts.AppendValues(treeiter, "tom", "[email protected]");

        filter = new Gtk.TreeModelFilter(contacts, null);
        // Specify the function that determines which rows to filter out and which ones to display
        filter.VisibleFunc = new Gtk.TreeModelFilterVisibleFunc(FilterTree);

        // Assign the filter as our treeview's model
        tv.Model = filter;

        // Show the window and everything on it
        window.ShowAll();
    }

    private void OnFilterEntryTextChanged(object o, System.EventArgs args)
    {
        // Since the filter text changed, tell the filter to re-determine which rows to display
        filter.Refilter();
    }

    private bool FilterTree(Gtk.TreeModel model, Gtk.TreeIter iter)
    {
        string contactname = model.GetValue(iter, 0).ToString();
        if (filterEntry.Text == "")
            return true;
        if (contactname.IndexOf(filterEntry.Text) > -1)
            return true;
        else
            return false;
    }
}

[我正在使用 mono 2.6.4 /monodevelop 2.4 / gtk -windows vista 上的锐利 2.12。]

Answer 1

似乎在过滤树模型中的行时，只有当行的所有父行也可见时，该行才可见。由于您的过滤函数隐藏了父节点，因此即使文本匹配，它也不会显示子节点。我修改了您的代码来说明这个问题：

现在，父节点之一以“test”开头。如果您输入“test”，您将看到过滤工作正常。

using System;
using Gtk;

public class TreeViewExample
{

public static void Main ()

{

    Gtk.Application.Init ();

    new TreeViewExample ();

    Gtk.Application.Run ();

}


Gtk.Entry filterEntry;
Gtk.TreeModelFilter filter;



public TreeViewExample ()
{

    // Create a Window

    Gtk.Window window = new Gtk.Window ("TreeView Example");

    window.SetSizeRequest (500,200);

    window.DeleteEvent+=delegate {Application.Quit();};



    // Create an Entry used to filter the tree

    filterEntry = new Gtk.Entry ();



    // Fire off an event when the text in the Entry changes

    filterEntry.Changed += OnFilterEntryTextChanged;



    // Create a nice label describing the Entry

    Gtk.Label filterLabel = new Gtk.Label ("Search:");



    // Put them both into a little box so they show up side by side

    Gtk.HBox filterBox = new Gtk.HBox ();

    filterBox.PackStart (filterLabel, false, false, 5);

    filterBox.PackStart (filterEntry, true, true, 5);



    // Create our TreeView

    Gtk.TreeView tv = new Gtk.TreeView ();



    // Create a box to hold the Entry and Tree

    Gtk.VBox box = new Gtk.VBox ();



    // Add the widgets to the box

    box.PackStart (filterBox, false, false, 5);

    box.PackStart (tv, true, true, 5);



    window.Add (box);





    //setting up columns and renderers





    Gtk.TreeViewColumn nameColumn = new Gtk.TreeViewColumn{Title="Name"}; 

    Gtk.CellRendererText nameCell = new Gtk.CellRendererText ();        

    nameColumn.PackStart (nameCell, true);









    Gtk.TreeViewColumn emailColumn = new Gtk.TreeViewColumn {Title="Email"}; 

    Gtk.CellRendererText emailCell = new Gtk.CellRendererText ();

    emailColumn.PackStart (emailCell, true);







    // Add the columns to the TreeView

    tv.AppendColumn (nameColumn);

    tv.AppendColumn (emailColumn);







    // Tell the Cell Renderers which items in the model to display

    nameColumn.AddAttribute (nameCell, "text", 0);

    emailColumn.AddAttribute (emailCell, "text", 1);







    // Create a model that will hold two strings 

    Gtk.TreeStore contacts = new Gtk.TreeStore (typeof (string), typeof (string));





    // Add some hierarchical data



    Gtk.TreeIter treeiter;





    //first root

    treeiter= contacts.AppendValues("testFRIENDS"); 



        // 2 children of first root

        contacts.AppendValues(treeiter, "testOgre", "[email protected]");

        contacts.AppendValues(treeiter, "testBee", "[email protected]");







    // second root

    treeiter= contacts.AppendValues("RELATIVES"); 



        // 3 children of second root

        contacts.AppendValues (treeiter,"Mommy","[email protected]");

        contacts.AppendValues (treeiter,"Daddy", "[email protected]");

        contacts.AppendValues (treeiter,"tom", "[email protected]");









    filter = new Gtk.TreeModelFilter (contacts, null);



    // Specify the function that determines which rows to filter out and which ones to display

    filter.VisibleFunc = new Gtk.TreeModelFilterVisibleFunc (FilterTree);



    // Assign the filter as our treeview's model

    tv.Model = filter;



    // Show the window and everything on it

    window.ShowAll ();

}



private void OnFilterEntryTextChanged (object o, System.EventArgs args)

{

    // Since the filter text changed, tell the filter to re-determine which rows to display

    filter.Refilter ();

}



private bool FilterTree (Gtk.TreeModel model, Gtk.TreeIter iter)

{

    string contactname = model.GetValue (iter, 0).ToString ();



    if (filterEntry.Text == "")

        return true;



    if (contactname.IndexOf (filterEntry.Text) > -1)

        return true;

    else

        return false;

}

当前结构的最

简单的解决方案是让过滤器函数根据模型中隐藏列中的值始终为“容器”节点（朋友和亲戚）返回 TRUE。它看起来不会完全像你想要的那样，但它会起作用。

GTK+ Treeview 教程虽然已经有一段时间没有更新了，但仍然是一个非常有用的资源满足您所有的 TreeView 需求。代码和示例都是 C 语言，但大部分仍然适用于 GTK#。

Answer 2

为了达到代码的正确功能，我建议您按以下方式修改它：

1.向您的类添加新字段 private filterBool = false;

2.修改您的 FilterTree 方法到此状态：

private bool FilterTree (Gtk.TreeModel model, Gtk.TreeIter iter)
{
string contactname = model.GetValue (iter, 0).ToString ();

if (filterEntry.Text == "")
    return true;

if (contactname.IndexOf (filterEntry.Text) > -1)
    return true;

if (model.IterHasChild(iter)) 
{
    filerBool = false;
    investigateChildNodes(model, iter); //method checking if currently investigated
                               //node has any child fulfilling filter contitions
    return filerBool;
}
return false;
}

3.添加缺少的方法

 private void investigateChildNodes(TreeModel model, TreeIter iter) 
    {       
        TreeIter childIter;
        model.IterChildren(out childIter, iter); 
        do
        {
            if (model.GetValue(childIter, 0).ToString().IndexOf(filterEntry.Text) > -1)
                filerBool = true;

            if (model.IterHasChild(childIter))
                investigateChildNodes(model, childIter);

        } while (model.IterNext(ref childIter));
    }

通过此修改，将检查每个节点是否有可能满足过滤条件的子节点。如果检测到任何节点，则不会丢弃该节点。

Answer 3

Tinki 版本运行完美。我唯一不喜欢的是私有变量。这可以通过使用 InvestigateChildrenNodes 函数中的返回值来消除。

    private bool InvestigateChildNodes(TreeModel model, TreeIter iter)
    {
        TreeIter childIter;
        model.IterChildren(out childIter, iter);

        bool result = false;
        do
        {
            if (model.GetValue(childIter, 0).ToString().Contains(FilterEntry.Text))
            {
                result = true;
                break;
            }

            if (model.IterHasChild(childIter))
            {
                result = InvestigateChildNodes(model, childIter);
                if (result)
                    break;
            }

        } while (model.IterNext(ref childIter));
        return result;
    }