使PropertyGrid控件的属性值可以显示多行的方法

第一步：重写UITypeEditor的GetEditStyle方法；

第二部：重写UITypeEditor的EditValue方法；

具体实现如下：

 using System;
 using System.Collections.Generic;
 using System.Linq;
 using System.Text;
 using System.Threading.Tasks;
 using System.Windows.Forms.Design;
 using System.Drawing.Design;
 using System.Windows.Forms;

 namespace PropertyGridDemo
 {
     public class PropertyGridRichText:UITypeEditor
     {
         public override UITypeEditorEditStyle GetEditStyle(System.ComponentModel.ITypeDescriptorContext context)
         {
             return UITypeEditorEditStyle.DropDown;
         }

         public override object EditValue(System.ComponentModel.ITypeDescriptorContext context,System.IServiceProvider provider,object value)
         {
             try
             {
                 IWindowsFormsEditorService edSvc = (IWindowsFormsEditorService)provider.GetService(typeof(IWindowsFormsEditorService));
                 if (edSvc != null)
                 {
                     if (value is string)
                     {
                         RichTextBox box = new RichTextBox();
                         box.Text = value as string;
                         edSvc.DropDownControl(box);
                         return box.Text;
                     }
                 }
             }
             catch (Exception ex)
             {
                 System.Console.WriteLine("PropertyGridRichText Error : " + ex.Message);
                 return value;
             }
             return value;
         }
     }
 }

调用方式为：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace PropertyGridDemo
{
    public class Person
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Sex { get; set; }

        [EditorAttribute(typeof(PropertyGridRichText), typeof(System.Drawing.Design.UITypeEditor)),Description("The person content!")]
        public string Content { get; set; }
    }
}

界面代码：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace PropertyGridDemo
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            propertyGrid1.SelectedObject = new Person();
        }
    }
}

界面实现效果：