Question

我很清楚我可以应用于类的每个属性的<System.ComponentModel.Browsable("False")>属性。是否可以将所有属性的Browsable属性的默认值设置为False？

以下代码编译并说明了我想要实现的目标，但遗憾的是它没有按预期工作：

<Browsable(False)>
Public Class SomeClass

    Public Property HiddenByDefaultProperty1 As Object
    Public Property HiddenByDefaultProperty2 As Object

    ...

    <Browsable(True)> Public Property BrowsableProperty As Object

End Class

为了达到我的目的，我必须将<Browsable(False)>应用于我不希望在我的DataGridView中显示的所有属性，这是很多代码混乱。

如果我只需要为要显示的属性指定<Browsable(True)>，那就太棒了。但是：有可能吗？

Answer 1

不，我不认为使用browsable属性可以实现这一点。但是，您可以通过实现ICustomTypeDescriptor接口来控制DataGridView将绑定到哪些属性。

<强>模型

C＃：

public class Foo : ICustomTypeDescriptor
{

    public string P1 { get; set; }
    public string P2 { get; set; }
    public string P3 { get; set; }
    public string P4 { get; set; }
    public string P5 { get; set; }
    public string P6 { get; set; }
    public string P7 { get; set; }
    public string P8 { get; set; }
    public string P9 { get; set; }

    PropertyDescriptorCollection ICustomTypeDescriptor.GetProperties(Attribute[] attributes)
    {

        var properties = new[] { "P1", "P3", "P7" };

        var descriptors = TypeDescriptor
            .GetProperties(typeof(Foo))
            .Cast<PropertyDescriptor>()
            .Where(p => properties.Any(s => s == p.Name))
            .ToArray();

        return new PropertyDescriptorCollection(descriptors);

    }

    AttributeCollection ICustomTypeDescriptor.GetAttributes()
    {
        return new AttributeCollection(null);
    }

    string ICustomTypeDescriptor.GetClassName()
    {
        return null;
    }

    string ICustomTypeDescriptor.GetComponentName()
    {
        return null;
    }

    TypeConverter ICustomTypeDescriptor.GetConverter()
    {
        return null;
    }

    EventDescriptor ICustomTypeDescriptor.GetDefaultEvent()
    {
        return null;
    }

    PropertyDescriptor ICustomTypeDescriptor.GetDefaultProperty()
    {
        return null;
    }

    object ICustomTypeDescriptor.GetEditor(Type editorBaseType)
    {
        return null;
    }

    EventDescriptorCollection ICustomTypeDescriptor.GetEvents()
    {
        return new EventDescriptorCollection(null);
    }

    EventDescriptorCollection ICustomTypeDescriptor.GetEvents(Attribute[] attributes)
    {
        return new EventDescriptorCollection(null);
    }

    PropertyDescriptorCollection ICustomTypeDescriptor.GetProperties()
    {
        return ((ICustomTypeDescriptor)this).GetProperties(null);
    }

    object ICustomTypeDescriptor.GetPropertyOwner(PropertyDescriptor pd)
    {
        return this;
    }
}

VB.Net：

Public Class Foo
    Implements ICustomTypeDescriptor

    Public Property P1 As String
    Public Property P2 As String
    Public Property P3 As String
    Public Property P4 As String
    Public Property P5 As String
    Public Property P6 As String
    Public Property P7 As String
    Public Property P8 As String
    Public Property P9 As String

    Private Function GetProperties(attributes() As Attribute) As PropertyDescriptorCollection Implements ICustomTypeDescriptor.GetProperties

        Dim properties = {"P1", "P3", "P7"}

        Dim descriptors = TypeDescriptor _
            .GetProperties(GetType(Foo)) _
            .Cast(Of PropertyDescriptor) _
            .Where(Function(p) properties.Any(Function(s) s = p.Name)) _
            .ToArray()

        Return New PropertyDescriptorCollection(descriptors)

    End Function

    Private Function GetAttributes() As AttributeCollection Implements ICustomTypeDescriptor.GetAttributes
        Return New AttributeCollection(Nothing)
    End Function

    Private Function GetClassName() As String Implements ICustomTypeDescriptor.GetClassName
        Return Nothing
    End Function

    Private Function GetComponentName() As String Implements ICustomTypeDescriptor.GetComponentName
        Return Nothing
    End Function

    Private Function GetConverter() As TypeConverter Implements ICustomTypeDescriptor.GetConverter
        Return Nothing
    End Function

    Private Function GetDefaultEvent() As EventDescriptor Implements ICustomTypeDescriptor.GetDefaultEvent
        Return Nothing
    End Function

    Private Function GetDefaultProperty() As PropertyDescriptor Implements ICustomTypeDescriptor.GetDefaultProperty
        Return Nothing
    End Function

    Private Function GetEditor(editorBaseType As Type) As Object Implements ICustomTypeDescriptor.GetEditor
        Return Nothing
    End Function

    Private Function GetEvents() As EventDescriptorCollection Implements ICustomTypeDescriptor.GetEvents
        Return New EventDescriptorCollection(Nothing)
    End Function

    Private Function GetEvents(attributes() As Attribute) As EventDescriptorCollection Implements ICustomTypeDescriptor.GetEvents
        Return New EventDescriptorCollection(Nothing)
    End Function

    Private Function GetProperties() As PropertyDescriptorCollection Implements ICustomTypeDescriptor.GetProperties
        Return DirectCast(Me, ICustomTypeDescriptor).GetProperties(Nothing)
    End Function

    Private Function GetPropertyOwner(pd As PropertyDescriptor) As Object Implements ICustomTypeDescriptor.GetPropertyOwner
        Return Me
    End Function

End Class

<强>的DataGridView：

C＃：

var list = new List<Foo>();

list.Add(new Foo());
list.Add(new Foo());
list.Add(new Foo());

this.dataGridView1.DataSource = list;

VB.Net：

Dim list As New List(Of Foo)

list.Add(New Foo())
list.Add(New Foo())
list.Add(New Foo())

Me.DataGridView1.DataSource = list

<强> PropertyGrid中：

C＃：

this.propertyGrid1.SelectedObject = new Foo();

VB.Net：

Me.PropertyGrid1.SelectedObject = New Foo()

Answer 2

如另一个答案所述，ICustomTypeDescriptor使您可以完全控制对象的元数据，但它需要大量的样板代码。对于列表绑定控件（如DataGridView，ListView等），ITypedList接口可以由列表源类实现，这更简单，但仍需要一些编码。在这两种情况下，如果您无法创建一些基类并从中继承所有类，那么只需标记您的＆＃34;不可浏览＆＃34;成员。
无论如何，还有另一种方式，这有点像hackish，但确实（几乎）完全符合你的要求。该行为由我称为NoBrowsableAttribute的自定义类提供。用法很简单：

// To turn it on
NoBrowsableAttribute.Enabled = true;
// To turn it off
NoBrowsableAttribute.Enabled = false;

请注意，启用后，它会更改应用程序内所有类的BrowsableAttribute默认行为。这是一个样本测试：

using System;
using System.ComponentModel;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;

namespace Samples
{
    public sealed class NoBrowsableAttribute : TypeDescriptionProvider
    {
        public static bool Enabled
        {
            get { return instance.enabled; }
            set { instance.enabled = value; }
        }
        private static readonly NoBrowsableAttribute instance = new NoBrowsableAttribute();
        private bool enabled;
        private NoBrowsableAttribute() : base(TypeDescriptor.GetProvider(typeof(BrowsableAttribute)))
        {
            TypeDescriptor.AddProvider(this, typeof(BrowsableAttribute));
        }
        public override Type GetReflectionType(Type objectType, object instance)
        {
            if (enabled && objectType == typeof(BrowsableAttribute)) return typeof(NoBrowsableAttribute);
            return base.GetReflectionType(objectType, instance);
        }
        public static readonly BrowsableAttribute Default = BrowsableAttribute.No;
    }

    static class Test
    {
        class Person
        {
            public int Id { get; set; }
            [Browsable(true)]
            public string Name { get; set; }
            [Browsable(true)]
            public string Description { get; set; }
            public int Age { get; set; }
        }
        [STAThread]
        static void Main()
        {
            NoBrowsableAttribute.Enabled = true;

            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            var data = Enumerable.Range(1, 10).Select(i => new Person { Id = i, Name = "Name" + i, Description = "Description" + i }).ToList();
            var form = new Form { StartPosition = FormStartPosition.CenterScreen, ClientSize = new Size(500, 300) };
            var split = new SplitContainer { Dock = DockStyle.Fill, Parent = form, FixedPanel = FixedPanel.Panel2, SplitterDistance = 300 };
            var dg = new DataGridView { Dock = DockStyle.Fill, Parent = split.Panel1 };
            var pg = new PropertyGrid { Dock = DockStyle.Fill, Parent = split.Panel2, ToolbarVisible = false, PropertySort = PropertySort.NoSort };
            dg.BindingContextChanged += (sender, e) => {
                var bm = dg.BindingContext[data];
                pg.SelectedObject = bm.Current;
                bm.CurrentChanged += (_sender, _e) => pg.SelectedObject = bm.Current;
            };
            dg.DataSource = data;
            Application.Run(form);
        }
    }
}

是否可以默认隐藏类的属性，例如在DataGridView中？

2 个答案: