C#—DataTable常见用法

1.构建DataTable数据源

DataTable dt_new= new DataTable();dt_new.Columns.Add("column1", typeof(string));   dt_new.Columns.Add("column2", typeof(string));  dt_new.Columns.Add("column3", typeof(Double));   DataRow dr = dt_new.NewRow();dr["column1"] = column1_value;dr["column2"] = column2_value;dr["column3"]=Convert.ToDouble(column3_value);//将DataRow加入数据表dt_new.Rows.Add(dr);

2.更改数据列数据类型

  //复制DataTable 结构不包含数据 DataTable dt_temp = dt_new.Clone(); dt_temp .Columns["column1"].DataType = typeof(Double);//更改列数据类型            //填充数据            foreach (DataRow row in dt_new.Rows)            {                if (!row["column1"].ToString().Equals("NULL"))                {                    dte_temp.ImportRow(row);//添加进新表                }            }

3.DataTable数据查询

 DataTable dt_tmp = new DataTable(); //注意，字符串值要加引号 string filterExpression = "device_id= '" + task.CompareDeviceID+"'";            DataRow[] arrayDR = dt_fix.Select(filterExpression);             if (arrayDR != null)             {             //转换成DataTable                 dt_tmp = ToDataTable(arrayDR);                            }

4.DataTable排序

//dt_fix和dt_fix_temp 为DataTabledt_fix.DefaultView.Sort = "device_id asc";//根据ID排序 升序,desc降序dt_fix_temp = dt_fix.DefaultView.ToTable();