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我在我的应用程序中有一个class命名的产品，我想显示它以在Form使用PropertyGrid控件中进行编辑。class产品有一个命名的fieldMaterialId，它指定了构成产品的材料合金。我希望当产品class显示在PropertyGrid控件中时，fieldMaterialId 会显示一个包含所有可用材料的下拉列表。物料清单由用户提供，因此必须在运行时定义。我尝试使用 aPropertyDescriptor来修改dataSourceTextToComboConverter的字段class。我已经注意到，检查 Visual Studio 中的 Locals，这dataSource是在变量的Converter属性下descriptor，但我不知道如何访问dataSource场地。我按照以下代码中的说明进行了尝试，但没有成功。有人可以告诉我正确的方法吗？

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Globalization;
using System.Windows.Forms;
using System.Reflection;

namespace PropertyGridDropDownList
{
    public class Product
    {
        [Browsable(true)]
        public string ProductName { get; set; }

        [TypeConverter(typeof(TextToComboConVerter))]
        [Browsable(true)]
        public string MaterialId { get; set; }

        [Browsable(true)]
        public double Wheight { get; set; }
    }

    public class TextToComboConVerter : StringConverter
    {
        public List<string> dataSource;

        public override bool GetStandardValuesSupported(ITypeDescriptorContext context)
        {
            return true;
        }

        public override bool GetStandardValuesExclusive(ITypeDescriptorContext context)
        {
            return true;
        }

        public override object ConvertFrom(ITypeDescriptorContext context,
                                           CultureInfo culture,
                                           object value)
        {
            return base.ConvertFrom(context, culture, value);
        }

        public override StandardValuesCollection GetStandardValues(ITypeDescriptorContext context)
        {
            return new StandardValuesCollection(dataSource);
        }
    }

    static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);

            //Actually this list is supplied by user through a input form.
            List<string> materialIdList = new List<string>();

            materialIdList.Add("Material01");
            materialIdList.Add("Material02");
            materialIdList.Add("Material03");
            materialIdList.Add("Material04");
            materialIdList.Add("Material05");

            //Create a instance of Product class.
            Product product = new Product()
            {
                ProductName = "Product01",
                MaterialId = "Material03",
                Wheight = 100
            };            

            //Define combobox for MaterialId.
            PropertyDescriptor descriptor = TypeDescriptor.GetProperties(product)["MaterialId"];
            descriptor.Converter.dataSource = materialIdList; //This fails

            //Show the Product class in a ProductGrid.
            //I would like that itens of materialIdList was showed
            //as a dropdown list in MaterialId field.
            using (PropertyGrid propertyGrid = new PropertyGrid
            {
                Dock = DockStyle.Fill,
                SelectedObject = product
            })
            using (Form form = new Form { Controls = { propertyGrid } })
            {
                Application.Run(form);
            }
        }
    }
}
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