的WinForms的DataGridView - 数据绑定到对象与列表属性（列的数目可变） [英] WinForms DataGridView - databind to an object with a list property (variable number of columns)

问题描述

我有一个.NET类，我想在一个DataGridView显示，默认绑定 - 将DGV的DataSource设置到对象 - 产生了我的要求，90％（即它的正确输出的公共属性，我可以添加排序容易）。

I have a .NET class I'd like to show in a DataGridView, and the default databinding - setting the DGV's DataSource to the object - produces 90% of my requirements (i.e. it's outputting the public properties correctly and I can add sorting easily).

不过，我需要绑定的属性之一是一个列表，其中包含一个需要在单独的列中的数据绑定的其他项目后的数据。我卡在如何最好地实现这一点。

However, one of the properties I need to bind is a List which contains data which needs to be in separate columns after the other databound items. I'm stuck on how best to implement this.

我的类看起来是这样的：

My class looks something like this:

public class BookDetails
{
    public string Title { get; set; }
    public int TotalRating { get; set; }
    public int Occurrence { get; set; }
    public List<int> Rating { get; set; }
}

在理想情况下，我会能够展开评级财产成若干个数字列给这样在运行时输出：

Ideally, I'd be able to expand that Rating property into a number of numeric columns to give an output like this at runtime:

标题|总评分|发生| R1 | R2 | R3 ... RN

Title | Total Rating | Occurrence | R1 | R2 | R3 ... RN

这也将是有用的总评分被计算为所有的个人收视率的总和，但我此刻的手动更新，没有问题。

It would also be useful to have Total Rating be calculated as the sum of all the individual ratings, but I'm updating that manually at the moment without issue.

推荐答案

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using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Windows.Forms;
public class BookDetails
{
    public string Title { get; set; }
    public int TotalRating { get; set; }
    public int Occurrence { get; set; }
    public List<int> Rating { get; set; }
}
class BookList : List<BookDetails>, ITypedList
{

    public PropertyDescriptorCollection GetItemProperties(PropertyDescriptor[] listAccessors)
    {
        var origProps = TypeDescriptor.GetProperties(typeof(BookDetails));
        List<PropertyDescriptor> newProps = new List<PropertyDescriptor>(origProps.Count);
        PropertyDescriptor doThisLast = null;
        foreach (PropertyDescriptor prop in origProps)
        {

            if (prop.Name == "Rating") doThisLast = prop;
            else newProps.Add(prop);
        }
        if (doThisLast != null)
        {
            var max = (from book in this
                       let rating = book.Rating
                       where rating != null
                       select (int?)rating.Count).Max() ?? 0;
            if (max > 0)
            {
                // want it nullable to account for jagged arrays
                Type propType = typeof(int?); // could also figure this out from List<T> in
                                              // the general case, but make it nullable
                for (int i = 0; i < max; i++)
                {
                    newProps.Add(new ListItemDescriptor(doThisLast, i, propType));
                }
            }
        }
        return new PropertyDescriptorCollection(newProps.ToArray());
    }

    public string GetListName(PropertyDescriptor[] listAccessors)
    {
        return "";
    }
}
class ListItemDescriptor : PropertyDescriptor
{
    private static readonly Attribute[] nix = new Attribute[0];
    private readonly PropertyDescriptor tail;
    private readonly Type type;
    private readonly int index;
    public ListItemDescriptor(PropertyDescriptor tail, int index, Type type) : base(tail.Name + "[" + index + "]", nix)
    {
        this.tail = tail;
        this.type = type;
        this.index = index;
    }
    public override object GetValue(object component)
    {
        IList list = tail.GetValue(component) as IList;
        return (list == null || list.Count <= index) ? null : list[index];
    }
    public override Type PropertyType
    {
        get { return type; }
    }
    public override bool IsReadOnly
    {
        get { return true; }
    }
    public override void SetValue(object component, object value)
    {
        throw new NotSupportedException();
    }
    public override void ResetValue(object component)
    {
        throw new NotSupportedException();
    }
    public override bool CanResetValue(object component)
    {
        return false;
    }
    public override Type ComponentType
    {
        get { return tail.ComponentType; }
    }
    public override bool ShouldSerializeValue(object component)
    {
        return false;
    }
}
static class Program
{
    [STAThread]
    static void Main()
    {
        Application.EnableVisualStyles();
        var data = new BookList {
            new BookDetails { Title = "abc", TotalRating = 3, Occurrence = 2, Rating = new List<int> {1,2,1}},
            new BookDetails { Title = "def", TotalRating = 3, Occurrence = 2, Rating = null },
            new BookDetails { Title = "ghi", TotalRating = 3, Occurrence = 2, Rating = new List<int> {3, 2}},
            new BookDetails { Title = "jkl", TotalRating = 3, Occurrence = 2, Rating = new List<int>()},
        };
        Application.Run(new Form
        {
            Controls = {
                new DataGridView {
                    Dock = DockStyle.Fill,
                    DataSource = data
                }
            }
        });

    }
}

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