Question

我正在编写一个扩展的树视图，只需要在我的TreeNode类中添加一些具有设计时支持的额外属性。

代码已经准备就绪，但此刻我完全坚持使用以下代码。我此时尝试的所有内容都会导致（另一个）例外......

也许有人知道如何进一步发展？我不知道了

using System;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.ComponentModel.Design.Serialization;
using System.Drawing.Design;
using System.Globalization;
using System.Reflection;
using System.Runtime.Serialization;
using System.Windows.Forms;

namespace MyProject.Forms
{
    public class MenuTreeView : TreeView
    {
        public MenuTreeView()
        {
            //
        }

    [Editor(typeof(MenuTreeNodeCollectionEditor), typeof(UITypeEditor))]
    //[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
    public new TreeNodeCollection Nodes
    {
        get
        {
            return base.Nodes;
        }
    }
}

[Serializable]
[DefaultProperty("Text")]
[TypeConverter(typeof(MenuTreeNodeConverter))]
public class MenuTreeNode : TreeNode, ISerializable
{
    private string description = "";

    public MenuTreeNode()
        : base()
    {
        //
    }

    public MenuTreeNode(string text)
        : base(text)
    {
        //
    }

    public MenuTreeNode(string text, string description)
        : base(text)
    {
        this.description = description;
    }

    public MenuTreeNode(string text, MenuTreeNode[] children)
        : base(text, children)
    {
        //
    }

    public override object Clone()
    {
        object clone = base.Clone();
        MenuTreeNode node = clone as MenuTreeNode;
        if (node != null)
        {
            node.Description = Description;
            return node;
        }
        else return clone;
    }

    void ISerializable.GetObjectData(SerializationInfo info, StreamingContext context)
    {
        Serialize(info, context);
    }

    protected override void Deserialize(SerializationInfo info, StreamingContext context)
    {
        Description = info.GetString("Description");

        base.Deserialize(info, context);
    }

    protected override void Serialize(SerializationInfo info, StreamingContext context)
    {
        info.AddValue("Description", Description);

        base.Serialize(info, context);
    }

    [DefaultValue("")]
    public string Description
    {
        get { return description; }
        set { description = value; }
    }
}

public class MenuTreeNodeConverter : TypeConverter
{
    public override bool CanConvertFrom(ITypeDescriptorContext context, Type type)
    {
        if (type == typeof(string))
        {
            return true;
        }

        return base.CanConvertFrom(context, type);
    }

    public override bool CanConvertTo(ITypeDescriptorContext context, Type type)
    {
        if (type == typeof(InstanceDescriptor) || type == typeof(string))
        {
            return true;
        }

        return base.CanConvertTo(context, type);
    }

    public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo info, object value)
    {
        if (value != null && value is string)
        {
            string[] items = ((string)value).Split(',');
            return new MenuTreeNode(items[0], items[1]);
        }

        return base.ConvertFrom(context, info, value);
    }

    public override object ConvertTo(ITypeDescriptorContext context, CultureInfo info, object value, Type type)
    {
        MenuTreeNode node = value as MenuTreeNode;
        if (value != null)
        {
            if (type == typeof(string))
            {
                return node.Text + "," + node.Description;
            }
            else if (type == typeof(InstanceDescriptor))
            {
                ConstructorInfo constructor = typeof(MenuTreeNode).GetConstructor(new Type[] { typeof(string), typeof(string) });
                return new InstanceDescriptor(constructor, new object[] { node.Text, node.Description }, true);
            }
        }

        return base.ConvertTo(context, info, value, type);
    }
}

public class MenuTreeNodeCollectionEditor : CollectionEditor
{
    public MenuTreeNodeCollectionEditor(Type t)
        : base(t)
    {
        //
    }

    protected override Type CreateCollectionItemType()
    {
        return typeof(MenuTreeNode);
    }

    protected override Type[] CreateNewItemTypes()
    {
        return new Type[] { typeof(MenuTreeNode) };
    }

    protected override object CreateInstance(Type itemType)
    {
        if (itemType == typeof(MenuTreeNode))
        {
            return new MenuTreeNode();
        }

        return base.CreateInstance(itemType);
    }

    protected override string GetDisplayText(object value)
    {
        MenuTreeNode node = value as MenuTreeNode;
        if (node != null)
        {
            return "MenuTreeNode: " + node.Text;
        }

        return base.GetDisplayText(value);
    }
}

}

[编辑] 将Treeview移动到另一个项目后，一切顺利。不要问我为什么......

但是：只保存属性Text和Description，因为设计器不为每个添加的节点创建局部变量。我怎样才能做到这一点？

[编辑] 最后，我得到了它的工作！多亏了这个：http://netcode.ru/dotnet/?lang=&katID=30&skatID=283&artID=7827

解决方案是从TypeConvertor中删除typeof（string），当类型为InstanceDescriptor时，只返回默认构造函数。

Answer 1

最后，我得到了它的工作！感谢这篇文章：http://netcode.ru/dotnet/?lang=&katID=30&skatID=283&artID=7827

解决方案是从TypeConvertor中删除typeof（string），当类型为InstanceDescriptor时，只返回默认构造函数即可完成工作。

扩展的treenode / treeview，几乎就在那里

1 个答案: