Question

我在datatable中有更多列（大约100列）。见下面的考试：

 Column 1 | Column 2 | Column 3 | ..... | Column n 
 1;Nick   | 1        | USA      | ..... | Value 1
 2;David  | 2        | Reston   | ..... | Value 2
 3;Marry  | 3        | Spain    | ..... | Value 3
 4;Join   | 4        | Italy 3  | .....  Value 4

Dictionary<string, string > dict = new Dictionary<string, string>();
dict.Add("Column_1", "asc");
dict.Add("Column_2", "asc");
dict.Add("Column_1", "desc");
...................
dict.Add("Column_n", "asc");

var myRows = from row in datatable.AsEnumerable()
             let myID = int.Parse(row.Field<string>("Column 2"))
             let name = row.Field<string>("Column 1").Split(';')[1]
             ....
             orderby myID ascending, name descending, ......, column n asc
             select row;

我的问题是如何循环词典中的所有项目以在词典中添加更多 let 语句和 orderby 所有列。

请帮我修理一下。我的英语不好，抱歉

Answer 1

Dictionary<string, string > dict = new Dictionary<string, string>();
dict.Add("col1", "ASC");
dict.Add("col2", "ASC");
dict.Add("col3", "DESC");
DataTable dt = new DataTable();
dt.Columns.Add("col1");
dt.Columns.Add("col2");
dt.Columns.Add("col3");
Random r = new Random();
for (int i = 0; i < 20; i++)
    dt.Rows.Add(r.Next(10), r.Next(4), r.Next(2));
string sort = "";
foreach (KeyValuePair<string, string> entry in dict)
    sort = sort + " " + entry.Key + " " + entry.Value + ",";
sort = sort.Substring(0, sort.Length - 1).Trim();
dt.DefaultView.Sort = sort;
dt = dt.DefaultView.ToTable();

如何在linq中添加多个let运算符和orderby

1 个答案: