.NET Datatable常用系列一

Datatable常用系列一

一、用作集合存储数据：

 DataTable dt = new DataTable("action");

            for (int i = 0; i < 10; i++)

            {

                dt.Columns.Add("action" + i);

            }

            for (int i = 0; i < dt.Columns.Count; i++)

            {

                DataRow dr = dt.NewRow();

                for (int j = 0; j < 10; j++)

                {

                    dr[j] = j;

                }

                dt.Rows.Add(dr);

            }

二、利用扩展方法AsEnumerable对集合进行刷选

decimal action9_Sum = dt.AsEnumerable().Sum(x => Convert.ToDecimal(x["action9"]));

            //....原型：

            decimal sum = 0m;

            foreach (DataRow item in dt.Rows)

            {

                if (item["action9"] != null)

                    sum += decimal.Parse(item["action9"].ToString());

            }

            List<object> list = dt.AsEnumerable().Select(x => x["action9"]).ToList();

三、利用dataview进行刷选

 DataTable dt3 = new DataView(dt)

            {

                Sort = "action9",

            }.ToTable();

            DataTable dt4 = new DataView(dt)

            {

                RowFilter = "action0='9'",

            }.ToTable();

四、group by：举例

var d3 = d1.AsEnumerable().GroupBy(x => new { t1 = x.Field<string>("time"), t2 = x.Field<string>("str1") })
.Select(x => new { time = x.Key.t1, str0 = x.Key.t2, c = x.Count() });

group by 前：

group by 后：

五、Xml转换

string xml = "<?xml version="1.0" encoding="UTF-8"?><root><a>1</a><b>2</b></root>";

            DataSet ds = new DataSet();

            StringReader sr = new StringReader(xml);

            ds.ReadXml(sr);

            DataTable dt5 = ds.Tables[0];

六、未完待续...