将字典列表转换为DataTable

Question

目前我们通过循环遍历列表和字典的每个值来完成此操作:

private DataTable ChangeToDictionary(List<Dictionary<string,int>> list)
       {
           DataTable datatTableReturn = new DataTable();

           if (list.Count() > 0)
           {
               Dictionary<string, int> haeders = list.ElementAt(0);
               foreach (var colHead in haeders)
               {
                   datatTableReturn.Columns.Add(colHead.Key);
               }
           }

           foreach (var row in list)
           {
               DataRow dataRow = datatTableReturn.NewRow();
               foreach (var col in row)
               {

                   dataRow[col.Key] = col.Value;
               }
               datatTableReturn.Rows.Add(dataRow);
           }
           return datatTableReturn;

       }

但有更好的方法吗？循环这么多次感觉并不好

Answer 1

上面的答案没有解决超过1行的字典问题.该解决方案解决了该问题.

static DataTable ToDataTable(List<Dictionary<string, int>> list)
{
    DataTable result = new DataTable();
    if (list.Count == 0)
        return result;

    var columnNames = list.SelectMany(dict=>dict.Keys).Distinct();
    result.Columns.AddRange(columnNames.Select(c=>new DataColumn(c)).ToArray());
    foreach (Dictionary<string,int> item in list)
    {
        var row = result.NewRow();
        foreach (var key in item.Keys)
        {
            row[key] = item[key];
        }

        result.Rows.Add(row);
    }

    return result;
}

static void Main(string[] args)
{
    List<Dictionary<string, int>> it = new List<Dictionary<string, int>>();
    Dictionary<string, int> dict = new Dictionary<string, int>();
    dict.Add("a", 1);
    dict.Add("b", 2);
    dict.Add("c", 3);
    it.Add(dict);
    dict = new Dictionary<string, int>();
    dict.Add("bob", 34);
    dict.Add("tom", 37);
    it.Add(dict);
    dict = new Dictionary<string, int>();
    dict.Add("Yip Yip", 8);
    dict.Add("Yap Yap", 9);
    it.Add(dict);

    DataTable table = ToDictionary(it);
    foreach (DataColumn col in table.Columns)
        Console.Write("{0}\t", col.ColumnName);
    Console.WriteLine();
    foreach (DataRow row in table.Rows)
    {
        foreach (DataColumn column in table.Columns)
            Console.Write("{0}\t", row[column].ToString());
        Console.WriteLine();
    }
    Console.ReadLine();

}

输出看起来像......

a       b       c       bob     tom     Yip Yip Yap Yap
1       2       3
                        34      37
                                        8       9

Answer 2

速度,优雅和可重用性不会在一起.你总是选择更重要的一个,并尝试平衡其他两个.

代码越快,它就越丑陋.它更漂亮,更不可重复使用.

这是一个"优雅"解决方案的例子,但这与它的可读性不同.

private static DataTable ToDictionary(List<Dictionary<string, int>> list)
{
    DataTable result = new DataTable();
    if (list.Count == 0)
        return result;

    result.Columns.AddRange(
        list.First().Select(r => new DataColumn(r.Key)).ToArray()
    );

    list.ForEach(r => result.Rows.Add(r.Select(c => c.Value).Cast<object>().ToArray()));

    return result;
}