使用IEnumerable将数据绑定到对象 <T> 属性-C＃

Question

I am quite new to databinding and I need some general directions on how to structure my application.

I have a database-like class like the following:

public class Database
{
    public string FileName { get; set; }
    public List<Entry> Entries { get { return backList.ToList(); } }

    BindingList<Entry> backList = new BindingList<Entry>();
    ...
}

where each entry is defined as follows:

public class Entry
{
    public string FileName { get; set; }
    public string Path { get; set; }
    FileInfo File { get; set; }
    public Dictionary<string, Field> Fields { get { return fields.ToDictionary(n => n.Name, f => f); } }
    HashSet<Field> fields = new HashSet<Field>();
    ...
}

I defined my object model like this because I know that each entry will for sure contain a FileName and a Path. But the number and type of "fields" each entry has it might be different (field is defined elsewhere as abstract). Assume some entries have the field "color", while others don't.

I want to display my entries in a dataGridView, and I want it to use dataBinding for this purpose. Assume I know in advance which columns need to be displayed (for sure FileName and Path, but also the fields "color" and "size").

Something like (pseudo-code):

dataGridView.Columns[0] --> Entry.FileName
dataGridView.Columns[1] --> Entry.Path
dataGridView.Columns[2] --> Entry.Fields["color"]
dataGridView.Columns[3] --> Entry.Fields["size"]

But from my understanding, it is possible only to bind dataGridView to Entry, which results in this:

dataGridView.Columns[0] --> Entry.FileName
dataGridView.Columns[1] --> Entry.Path
dataGridView.Columns[2] --> Entry.Fields {collection}

Any ideas?

---

EDIT:

Example for Servy:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Dynamic;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace DataBindingTest
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            InitDataGridView();
        }

        void InitDataGridView()
        {
            DataGridView dgv = new DataGridView();
            dgv.AutoGenerateColumns = true;
            dgv.Dock = DockStyle.Fill;
            this.Controls.Add(dgv);

            Database db = new Database();

            string[] colors = new string[5]{"red","orange","yellow","green","blue"};

            for (int i = 0; i < 5; i++)
            {
                db.Add(
                    new Entry(
                        @"C:\Test\file_" + i + ".jpg",
                        new SingleField("color", colors[i]),
                        new DateField("date_created", DateTime.Now.AddDays((int)i))
                            )
                        );
            }

            var query = db.Entries.Select(entry => 
            {
                IDictionary<string, object> mappings = new ExpandoObject();
                dynamic newEntry = mappings;
                newEntry.FileName = entry.FileName;
                newEntry.Path = entry.Path;
                foreach (var field in entry.Fields)
                {
                    mappings[field.Key] = field.Value;
                }
                return newEntry;
            });

            dgv.DataSource = query.ToList();    //  Empty dataGridView
            //dgv.DataSource = db.Entries;      //  Populated dataGridView
        }
    }

    public class Database
    {
        public string FileName { get; set; }

        BindingList<Entry> entries = new BindingList<Entry>();
        public BindingList<Entry> Entries { get { return entries; } }

        public void Add(Entry newEntry)
        {
            //  ToDo: code for checking newEntry
            //
            entries.Add(newEntry);
        }
    }

    public class Entry
    {
        public string FileName { get; set; }
        public string Path { get; set; }
        FileInfo File { get; set; }

        public Dictionary<string, Field> Fields { get { return fields.ToDictionary(n => n.Name, f => f); } }
        HashSet<Field> fields = new HashSet<Field>();

        public Entry(string fileName, params Field[] fieldParams)
        {
            File = new FileInfo(fileName);
            FileName = File.Name;
            Path = File.Directory.FullName;

            foreach (Field f in fieldParams)
            {
                fields.Add(f);
            }
        }
    }

    public abstract class Field
    {
        public string Name { get; protected set; }
        public object Value { get; protected set; }
        public FieldType Type { get; protected set; }

        public Field(string name, object value)
        {
            Name = name;
            Value = value;
        }
    }

    public class SingleField : Field
    {
        public SingleField(string name, string value) : base (name, value)
        {
            Type = FieldType.Single;
        }
    }

    public class MultipleField : Field
    {
        public MultipleField(string name, params string[] values) : base (name, values)
        {
            Type = FieldType.Multiple;
        }
    }

    public class DateField : Field
    {
        public DateField(string name, DateTime date) : base (name, date)
        {
            Type = FieldType.Date;
        }
    }

    public enum FieldType
    {
        Single,
        Multiple,
        Date
    }
}

Answer 1

You can use an ExpandoObject to create a bindable object with properties determined at runtime. You'll need to create one for each of your entries.

var query = entries.Select(entry => 
{
    IDictionary<string, object> mappings = new ExpandoObject();
    dynamic newEntry = mappings;
    newEntry.FileName = entry.FileName;
    newEntry.Path = entry.Path;
    foreach(var field in fields)
        mappings[field.Key] = field.Value);
    return newEntry;
});