如何在 propertygrid c# 的属性中设置 BrowseAttribute true 或 false？ [复制]

Question

可能重复：
Conditional “Browsable” Attribute

我定义了具有一些属性的AppSettings 类。在我的表单中，当我click Button1 时，我想显示属性 1 和 2（1,2 显示，其他属性隐藏或不显示），当click Button2 时，我想显示属性 2 和 3（1 隐藏， 2,3是显示，其他属性是隐藏还是不显示），怎么办？

public class AppSettings
{
    [BrowsableAttribute(true), CategoryAttribute("Document Settings"), DefaultValueAttribute(true)]
    public bool SaveOnClose{ get; set; }

    [BrowsableAttribute(true), CategoryAttribute("Global Settings"), ReadOnlyAttribute(true), DefaultValueAttribute("Welcome to AppDev!")]
    public string GreetingText { get; set; }

    [BrowsableAttribute(true), DescriptionAttribute("The rate in milliseconds that the text will repeat."), CategoryAttribute("Global Settings"), DefaultValueAttribute(10)]
    public int MaxRepeatRate { get; set; }

    [BrowsableAttribute(true), CategoryAttribute("Global Settings"), DefaultValueAttribute(4)]
    public int ItemsInMRUList { get; set; }

    [BrowsableAttribute(true), DefaultValueAttribute(false)]
    public bool SettingsChanged { get; set; }

    [BrowsableAttribute(true), CategoryAttribute("Version"), DefaultValueAttribute("1.0"), ReadOnlyAttribute(true)]
    public string AppVersion { get; set; }
}

我想动态地将BrowseAttribute 更改为真或假。我该怎么做？

表格代码是：

AppSettings AppSet = new AppSettings();

AppSet.AppVersion = "2.3";
AppSet.SaveOnClose = true;
AppSet.GreetingText = "Welcome to Dar!";
AppSet.ItemsInMRUList = 4;
AppSet.MaxRepeatRate = 10;
AppSet.SettingsChanged = false;

...

propertyGrid1.SelectedObject = AppSet;

此更改有错误：

public static bool state = true;
BrowsableAttribute(state)

错误：

属性参数必须是常量表达式，typeof 表达式 或属性参数类型的数组创建表达式

Answer 1

对于过滤，我只需更改PropertyGrid 的BrowsableAttributes。在下文中，我：

• 定义一个自定义属性[DisplayMode(...)]，它描述了什么时候应该可见
  • 覆盖 IsMatch 以指示何时应将属性视为等效
• 用属性修饰你的类型AppSettings的一些设置
• 更改网格上的BrowsableAttributes，指定特定的DisplayModeAttribute，然后显示
• 启用不同的集合重复

代码如下：

using System.ComponentModel;
using System;
using System.Windows.Forms;

[AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)]
public class DisplayModeAttribute : Attribute
{
    private readonly string mode;
    public DisplayModeAttribute(string mode)
    {
        this.mode = mode ?? "";
    }
    public override bool Match(object obj)
    {
        var other = obj as DisplayModeAttribute;
        if (other == null) return false;

        if (other.mode == mode) return true;

        // allow for a comma-separated match, in either direction
        if (mode.IndexOf(',') >= 0)
        {
            string[] tokens = mode.Split(',');
            if (Array.IndexOf(tokens, other.mode) >= 0) return true;
        }
        else if (other.mode.IndexOf(',') >= 0)
        {
            string[] tokens = other.mode.Split(',');
            if (Array.IndexOf(tokens, mode) >= 0) return true;
        }
        return false;
    }
}

public class AppSettings
{
    [DisplayMode("A"), CategoryAttribute("Document Settings"), DefaultValueAttribute(true)]
    public bool SaveOnClose { get; set; }

    [DisplayMode("A,B")]
    [CategoryAttribute("Global Settings"), ReadOnlyAttribute(true), DefaultValueAttribute("Welcome to AppDev!")]
    public string GreetingText { get; set; }

    [DisplayMode("B"), BrowsableAttribute(true), DescriptionAttribute("The rate in milliseconds that the text will repeat."), CategoryAttribute("Global Settings"), DefaultValueAttribute(10)]
    public int MaxRepeatRate { get; set; }

    [BrowsableAttribute(true), CategoryAttribute("Global Settings"), DefaultValueAttribute(4)]
    public int ItemsInMRUList { get; set; }

    [BrowsableAttribute(true), DefaultValueAttribute(false)]
    public bool SettingsChanged { get; set; }

    [BrowsableAttribute(true), CategoryAttribute("Version"), DefaultValueAttribute("1.0"), ReadOnlyAttribute(true)]
    public string AppVersion { get; set; }
}
static class Program
{
    [STAThread]
    static void Main()
    {
        using (var form = new Form())
        using (var grid = new PropertyGrid())
        {
            grid.Dock = DockStyle.Fill;
            grid.SelectedObject = new AppSettings();
            grid.BrowsableAttributes = new AttributeCollection(
                new DisplayModeAttribute("A"));
            form.Controls.Add(grid);
            form.ShowDialog();

            grid.BrowsableAttributes = new AttributeCollection(
                new DisplayModeAttribute("B"));
            form.ShowDialog();
        }
    }
}