IEnumerable到字符串

Question

我有一个返回的DataTable

IDs
,1
,2
,3
,4
,5
,100
,101

我想将其转换为单个字符串值,即:

,1,2,3,4,5,100,101

如何重写以下内容以获取单个字符串

var _values = _tbl.AsEnumerable().Select(x => x);

Answer 1

var singleString = string.Join(",", _values.ToArray() );

Answer 2

写一个扩展方法,如

public static String AppendAll(this IEnumerable<String> collection, String seperator)
{
    using (var enumerator = collection.GetEnumerator())
    {
        if (!enumerator.MoveNext())
        {
            return String.Empty;
        }

        var builder = new StringBuilder().Append(enumerator.Current);

        while (enumerator.MoveNext())
        {
            builder.Append(seperator).Append(enumerator.Current);
        }

        return builder.ToString();
    }
}

并假设前一个表达式的结果是IEnumerable <String>,请调用:

var _values = _tbl.AsEnumerable().Select(x => x).AppendAll(String.Empty);    

Answer 3

 String.Join(
      ",",
      _tbl.AsEnumerable()
          .Select(r => r.Field<int>("ID").ToString())
          .ToArray())