的DataGridView绑定到一个词典 [英] DataGridView bound to a Dictionary

问题描述

我有一个词典包含项目和价格。该项目是独一无二的，但慢慢的添加，并通过应用程序生命周期更新（即我不知道项字符串提前）。我想这种结构绑定到一个DataGridView，这样我就可以证明我的表上的更新，是这样的：

I have a Dictionary that contains items and prices. The items are unique but slowly get added and updated through the lifetime of the application (that is, I don't know the item strings in advance). I would like to bind this structure to a DataGridView, so I can show updates on my Form, something like:

Dictionary<string, double> _priceData = new Dictionary<string, double>();
BindingSource _bindingSource = new BindingSource();
dataGridView1.DataSource = _bindingSource;
_bindingSource.DataSource = _priceData;

但不能，因为词典不执行的IList （或 IListSource ， IBindingList的或 IBindingListView ）。

But cannot, since Dictionary does not implement IList (or IListSource, IBindingList, or IBindingListView).

有没有办法来实现这一目标？我需要保持项目的唯一列表，同时也更新了价格的现有项目，因此词典是理想的数据结构我想，但我不能找到一种方法显示我的表上的数据。

Is there a way to achieve this? I need to keep a unique list of items, but also update the price for an existing item, so a Dictionary is the ideal data structure I think, but I cannot find a way to display the data on my Form.

更新：

马克的建议，下面的作品非常漂亮，但我仍然不知道如何执行过程中更新的DataGridView。

Marc's suggestion below works very nicely, but I'm still not sure how to update the DataGridView during execution.

我有一个类级变量：

private DictionaryBindingList<string, decimal> bList; 

然后实例，在主要（）：

bList = new DictionaryBindingList<string,decimal>(prices); 
dgv.DataSource = bList; 

程序执行期间然后，如果一个新的条目被添加到词典：

Then during program execution if a new entry is added to the dictionary:

prices.Add("foobar", 234.56M); bList.ResetBindings(); 

我认为这将刷新DataGridView的。为什么不呢？

I thought that would refresh the DataGridView. Why not?

推荐答案

有与词典的几个问题;第一个是（如你发现）它不实施必要的的IList / IListSource 。第二个是，没有保证为了将产品（实际上，没有索引），从而使由索引随机访问（而不是通过键）是不可能的。

There are a couple of issues with Dictionary; the first is (as you've found) it doesn't implement the necessary IList/IListSource. The second is that there is no guaranteed order to the items (and indeed, no indexer), making random access by index (rather than by key) impossible.

但是......它可能是可行的一些有些雾里看花;类似如下：

However... it is probably doable with some some smoke and mirrors; something like below:

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

static class Program
{
    [STAThread]
    static void Main()
    {
        Dictionary<string, decimal> prices =
            new Dictionary<string, decimal>();
        prices.Add("foo", 123.45M);
        prices.Add("bar", 678.90M);

        Application.EnableVisualStyles();
        Form form = new Form();
        DataGridView dgv = new DataGridView();
        dgv.Dock = DockStyle.Fill;
        form.Controls.Add(dgv);
        var bl = prices.ToBindingList();
        dgv.DataSource = bl;
        Button btn = new Button();
        btn.Dock = DockStyle.Bottom;
        btn.Click += delegate
        {
            prices.Add(new Random().Next().ToString(), 0.1M);
            bl.Reset();
        };
        form.Controls.Add(btn);
        Application.Run(form);
    }

    public static DictionaryBindingList<TKey, TValue>
        ToBindingList<TKey, TValue>(this IDictionary<TKey, TValue> data)
    {
        return new DictionaryBindingList<TKey, TValue>(data);
    }
    public sealed class Pair<TKey, TValue>
    {
        private readonly TKey key;
        private readonly IDictionary<TKey, TValue> data;
        public Pair(TKey key, IDictionary<TKey, TValue> data)
        {
            this.key = key;
            this.data = data;
        }
        public TKey Key { get { return key; } }
        public TValue Value
        {
            get
            {
                TValue value;
                data.TryGetValue(key, out value);
                return value;
            }
            set { data[key] = value; }
        }
    }
    public class DictionaryBindingList<TKey, TValue>
        : BindingList<Pair<TKey, TValue>>
    {
        private readonly IDictionary<TKey, TValue> data;
        public DictionaryBindingList(IDictionary<TKey, TValue> data)
        {
            this.data = data;
            Reset();
        }
        public void Reset()
        {
            bool oldRaise = RaiseListChangedEvents;
            RaiseListChangedEvents = false;
            try
            {
                Clear();
                foreach (TKey key in data.Keys)
                {
                    Add(new Pair<TKey, TValue>(key, data));
                }
            }
            finally
            {
                RaiseListChangedEvents = oldRaise;
                ResetBindings();
            }
        }

    }
}

请注意，使用自定义的扩展方法是完全可选的，并且可以去除在C＃2.0等，只需使用新DictionaryBindingList＆LT;字符串，小数＆GT;（价格）代替。

Note that the use of a custom extension method is entirely optional, and can be removed in C# 2.0, etc. by just using new DictionaryBindingList<string,decimal>(prices) instead.

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