C# 如何从对象列表填充树视图

How to populate a treeview from a list of objects

提问by user2346200

I'm having a problem populating my treeview from my list of objects. I've been looking for solutions on google, I found some topic close to my problem, but none of them solved it.

我在从对象列表填充树视图时遇到问题。我一直在 google 上寻找解决方案，我找到了一些接近我的问题的主题，但没有一个解决它。

I have a List with properties for each object : Name and Group.

我有一个包含每个对象属性的列表：名称和组。

I would like to populate my treeview like below :

我想像下面一样填充我的树视图：

+---Group 1
|   |
|   +--------object.Name <-- 
|   +--------object.Name <-- all objects with object.Group = Group 1
|   +--------object.Name <--
|
+---Group 2
|   |
|   +--------object.Name <-- 
|   +--------object.Name <-- all objects with object.Group = Group 2
|   +--------object.Name <--
|

and so on.

等等。

Thanks.

谢谢。

采纳答案by user2346200

Worked very well, thanks. I've just added a few lines at the beginning and at the end of the else as below.

工作得很好，谢谢。我刚刚在 else 的开头和结尾添加了几行，如下所示。

private void PopulateTreeView()
    {
        ListOfObjectsSorted = ListOfObjects.OrderBy(r => r.Group).ToList();
        var topNode = new TreeNode("Select all");
        treeView1.Nodes.Add(topNode);
        string currentGroup = ListOfObjectsSorted.First().Group;
        var treeNodes = new List<TreeNode>();
        var childNodes = new List<TreeNode>();
        foreach (Object obj in ListOfObjectsSorted )
        {
            if (currentGroup == rule.Group)
                childNodes.Add(new TreeNode(obj.Name));
            else
            {
                if (childNodes.Count > 0)
                {
                    treeNodes.Add(new TreeNode(currentGroup, childNodes.ToArray()));
                    childNodes = new List<TreeNode>();
                }
                childNodes.Add(new TreeNode(obj.Name));
                currentGroup = obj.Group;
            }
        }
        if (childNodes.Count > 0)
        {
            treeNodes.Add(new TreeNode(currentGroup, childNodes.ToArray()));
        }
        treeView1.Nodes[0].Nodes.AddRange(treeNodes.ToArray());
    }

回答by David Cummins

Is your problem technical, or just how to approach it? You could sort by object.Group, and then create a top level node every time the group changes.

您的问题是技术问题还是解决方法？您可以按 object.Group 排序，然后在每次组更改时创建一个顶级节点。

Edit: Here's some sample code below, I have not tested it so treat it more as a guideline:

编辑：下面是一些示例代码，我尚未对其进行测试，因此将其更多地视为指导：

string currentGroup = null;
List<TreeNode> treeNodes = new List<TreeNode>();
List<TreeNode> childNodes = new List<TreeNode>();
foreach (BusinessObject obj in objectList)
{
    if (currentGroup == obj.Group)
        childNodes.Add(new TreeNode(obj.Name));
    else
    {
        if (childNodes.Count > 0)
        {
            treeNodes.Add(new TreeNode(currentGroup, childNodes.ToArray()));
            childNodes = new List<TreeNode>();
        }
        currentGroup = obj.Group;
    }
}
if (childNodes.Count > 0)
{
    treeNodes.Add(new TreeNode(currentGroup, childNodes.ToArray()));
}
treeView.Nodes.AddRange(treeNodes.ToArray());

回答by tibi

Here some in VB...

这里有一些在 VB 中...

Try

尝试

        Me.Cursor = Cursors.WaitCursor
        If rtb.Visible Then line = rtb.Lines
        Dim i, j As Integer
        Dim myLst As New ListBox
        Dim nod0 As New TreeNode
        Dim nod1 As New TreeNode
        Dim nodGet As New TreeNode
        Dim nodSet As New TreeNode
        'Aktualna pozicia
        If trw.SelectedNode Is Nothing Then
        Else
            nodGet = trw.SelectedNode
        End If

        For Each nod0 In trw.Nodes
            If nod0.IsExpanded Then
                myLst.Items.Add(nod0.Tag)
                For Each nod1 In nod0.Nodes
                    If nod1.IsExpanded Then myLst.Items.Add(nod1.Tag)
                Next
            End If
        Next

        Dim cntr() As Integer = {-1, -1, -1}

        trw.Nodes.Clear()
        trw.ShowPlusMinus = False
        trw.ShowRootLines = False
        trw.CheckBoxes = False
        For i = 0 To UBound(line)
            If Mid(line(i), 1, 1) = "\" Then
                j = line(i).IndexOf(dod)
                If j > 0 Then
                    s = Mid(line(i), 1, j)
                Else
                    s = line(i)
                End If
                If Mid(s, 1, 4) = "\\" Then
                    trw.Nodes.Add(Mid(s, 5))
                    cntr(0) = cntr(0) + 1
                    cntr(1) = -1
                    cntr(2) = -1
                    trw.Nodes(cntr(0)).Tag = s
                    trw.Nodes(cntr(0)).ImageIndex = 4
                    trw.Nodes(cntr(0)).SelectedImageIndex = 5
                    If trw.Nodes(cntr(0)).Tag = nodGet.Tag Then nodSet = trw.Nodes(cntr(0))
                Else
                    If Mid(s, 1, 3) = "\\" Then
                        If cntr(0) = -1 Then trw.Nodes.Add("...") : cntr(0) = 0 : cntr(1) = -1
                        trw.Nodes(cntr(0)).Nodes.Add(Mid(s, 4))
                        cntr(1) = cntr(1) + 1
                        cntr(2) = -1
                        trw.Nodes(cntr(0)).Nodes(cntr(1)).Tag = trw.Nodes(cntr(0)).Tag.ToString & eol & s
                        trw.Nodes(cntr(0)).Nodes(cntr(1)).ImageIndex = 1
                        trw.Nodes(cntr(0)).Nodes(cntr(1)).SelectedImageIndex = 2
                        If trw.Nodes(cntr(0)).Nodes(cntr(1)).Tag = nodGet.Tag Then nodSet = trw.Nodes(cntr(0)).Nodes(cntr(1))
                    Else
                        If Mid(s, 1, 2) = "\" Then
                            If cntr(0) = -1 Then trw.Nodes.Add("...") : cntr(0) = 0 : cntr(1) = -1
                            If cntr(1) = -1 Then trw.Nodes(cntr(0)).Nodes.Add("...") : cntr(1) = 0 : cntr(2) = -1
                            trw.Nodes(cntr(0)).Nodes(cntr(1)).Nodes.Add(Mid(s, 3))
                            cntr(2) = cntr(2) + 1
                            trw.Nodes(cntr(0)).Nodes(cntr(1)).Nodes(cntr(2)).Tag = trw.Nodes(cntr(0)).Nodes(cntr(1)).Tag.ToString & eol & s
                            trw.Nodes(cntr(0)).Nodes(cntr(1)).Nodes(cntr(2)).ImageIndex = 3
                            trw.Nodes(cntr(0)).Nodes(cntr(1)).Nodes(cntr(2)).SelectedImageIndex = 4
                            If trw.Nodes(cntr(0)).Nodes(cntr(1)).Nodes(cntr(2)).Tag = nodSet.Tag Then nodSet = trw.Nodes(cntr(0)).Nodes(cntr(1)).Nodes(cntr(2))
                        End If
                    End If
                End If
            End If
        Next i
        'Navrat na aktualnu poziciu
        Application.DoEvents()
        For i = 0 To myLst.Items.Count - 1
            For Each nod0 In trw.Nodes
                If nod0.Tag = myLst.Items(i).ToString Then nod0.Expand()
                For Each nod1 In nod0.Nodes
                    If nod1.Tag = myLst.Items(i).ToString Then nod1.Expand()
                Next
            Next
        Next i
        Application.DoEvents()
        If nodSet.Tag <> "" Then trw.SelectedNode = nodSet
    Catch ex As Exception
        MsgBox(ex.ToString, MsgBoxStyle.Exclamation)
    Finally
        Me.Cursor = Cursors.Default
    End Try

回答by PrepucioArgentino

5 years later....

5年后……

Call >> PrintProperties(null, yourObject, 0);

调用 >> PrintProperties(null, yourObject, 0);

   public void PrintProperties(TreeNode parentNode, object obj, int indent)
    {

        if (obj == null) return;
        string indentString = new string(' ', indent);
        Type objType = obj.GetType();
        PropertyInfo[] properties = objType.GetProperties();
        foreach (PropertyInfo property in properties)
        {
            object propValue = new object();
            if (property.CanRead)
                propValue = property.GetValue(obj, null);
            if (IsSimpleType(property.PropertyType))
            {
                //Console.WriteLine("{0}{1}:", indentString, property.Name);
                if (parentNode != null)
                {
                    parentNode.Nodes.Add(property.Name, property.Name +": " + (propValue != null ? propValue.ToString() : string.Empty));
                }
                else
                {
                    treeView.Nodes.Add(property.Name, property.Name + ": " + (propValue != null ? propValue.ToString() : string.Empty));
                }

            }

            else if (typeof(IEnumerable).IsAssignableFrom(property.PropertyType))
            {
                TreeNode node;
                if (parentNode != null)
                {
                    node = parentNode.Nodes.Add(property.Name, property.Name);
                }
                else
                {
                    node = treeView.Nodes.Add(property.Name, property.Name);
                }

                //Console.WriteLine("{0}{1}:", indentString, property.Name);
                IEnumerable enumerable = (IEnumerable)propValue;
                foreach (object child in enumerable)
                    PrintProperties(node, child, indent + 2);
            }
            else
            {

                TreeNode node;
                if (parentNode != null)
                {
                    node = parentNode.Nodes.Add(property.Name, property.Name);
                }
                else
                {
                    node = treeView.Nodes.Add(property.Name, property.Name);
                }

                PrintProperties(node, propValue, indent + 2);
            }
        }
    }

    public static bool IsSimpleType(Type type)
    {
        return
            type.IsValueType ||
            type.IsPrimitive ||
            new Type[]
            {
        typeof(String),
        typeof(Decimal),
        typeof(DateTime),
        typeof(DateTimeOffset),
        typeof(TimeSpan),
        typeof(Guid)
            }.Contains(type) ||
            Convert.GetTypeCode(type) != TypeCode.Object;
    }