如何在“ CollectionEditor”对话框中为属性启用默认值 [英] How to enable Default Values for properties in a 'CollectionEditor' dialog

问题描述

请先阅读整个问题，以了解位置，我将能够重置属性的默认值。

Please read entire question first to understand where I would have the ability to reset the default value of a property.

在定义可以可视化设计的自定义类时，可以使用以下模式来实现集合编辑器来修改列表，数组，集合等属性：

When defining a custom class that can be visually designed, one can implement a collections editor to modify properties which are lists, arrays, collections, using the following pattern:

[Editor(typeof(CollectionEditor), typeof(UITypeEditor)),
    DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
public ElementCollection Elements
{
    get;
}

编辑元素此类的属性现在将启动 CollectionEditor 对话框，左侧是成员列表，而在列表中是 PropertyGrid

Editing the Elements property of this class will now launch a CollectionEditor dialog, with a list of members on the left and a PropertyGrid on the right.

问题是，似乎此属性网格的上下文菜单已禁用。因此，我无法右键单击属性以尽管已定义 [DefaultValue] 属性，但仍将其值重置为默认值。

The problem is, it appears that context menus are disabled for this property grid. Therefore, I cannot right click on a property to 'reset' its value to default, despite having a [DefaultValue] attribute defined.

但是，可以识别 DefaultValue 属性，因为该属性未序列化（并且正确显示在

Yet, the DefaultValue attribute is recognized, because the property is not serialized (and correctly displayed in unbolded text within the grid).

我想知道如何在 PropertyGrid 此上下文菜单 $ c>来自 CollectionEditor 对话框：

I would like to know how to enable this context menu on the PropertyGrid from the CollectionEditor dialog:

或者，可以通过任何方式（热键，等）实施以能够重置这些收集项属性。

or alternatively, any way (hot key, etc.) that can be implemented to be able to reset these collection item properties.

推荐答案

您可以继承 CollectionEditor 类，然后覆盖 CreateCollectionForm 方法，在集合编辑器表单中找到属性网格，然后注册包含属性网格 Reset 菜单项的 ContextMenuStrip ，然后使用< a href = https://msdn.microsoft.com/zh-cn/library/system.windows.forms.propertygrid.resetselectedproperty(v=vs.110).aspx rel = nofollow noreferrer> ResetSelectedProperty ：

You can create your own collection editor inheriting CollectionEditor class and then override CreateCollectionForm method, find property grid in the collection editor form and then register a ContextMenuStrip containing a Reset menu item for property grid, then reset the property using ResetSelectedProperty:

public class MyCollectionEditor : CollectionEditor
{
    public MyCollectionEditor() : base(typeof(Collection<MyElement>)) { }
    protected override CollectionForm CreateCollectionForm()
    {
        var form = base.CreateCollectionForm();
        var grid = form.Controls.Find("propertyBrowser", true).First() as PropertyGrid;
        var menu = new ContextMenuStrip();
        menu.Items.Add("Reset", null, (s, e) => { grid.ResetSelectedProperty(); });
        //Enable or disable Reset menu based on selected property
        menu.Opening += (s, e) =>
        {
            if (grid.SelectedGridItem != null && grid.SelectedObject != null &&
                grid.SelectedGridItem.PropertyDescriptor.CanResetValue(null))
                menu.Items[0].Enabled = true;
            else
                menu.Items[0].Enabled = false;
        };
        grid.ContextMenuStrip = menu;
        return form;
    }
}

并以此方式装饰收藏属性：

And decorate your collection property this way:

[Editor(typeof(MyCollectionEditor), typeof(UITypeEditor))]
[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
public Collection<MyElement> MyElements { get; private set; }

按照这种方法，您可以简单地添加分隔符，命令和描述菜单。

Following this approach you can simply add a separator, commands and description menus.

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