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var query = from g in dt_stu.AsEnumerable() group g by new { t1 = g.Field<string>("STU_ID"), t2 = g.Field<string>("CLASS_ID") } into m select new { STU_ID = m.Key.t1, CLASS_ID=m.Key.t2, 成绩总合计 = m.Sum(a => a.Field<decimal>("成绩")), 优秀人数 = m.Count(a => a.Field<decimal>("成绩")>95) }; DataTable dt_article = UserClass.ToDataTable(query); /// <summary> /// LINQ返回DataTable类型 /// </summary> /// <typeparam name="T"> </typeparam> /// <param name="varlist"> </param> /// <returns> </returns> public static DataTable ToDataTable<T>(IEnumerable<T> varlist) { DataTable dtReturn = new DataTable(); // column names PropertyInfo[] oProps = null; if (varlist == null) return dtReturn; foreach (T rec in varlist) { if (oProps == null) { oProps = ((Type)rec.GetType()).GetProperties(); foreach (PropertyInfo pi in oProps) { Type colType = pi.PropertyType; if ((colType.IsGenericType) && (colType.GetGenericTypeDefinition() == typeof(Nullable<>))) { colType = colType.GetGenericArguments()[0]; } dtReturn.Columns.Add(new DataColumn(pi.Name, colType)); } } DataRow dr = dtReturn.NewRow(); foreach (PropertyInfo pi in oProps) { dr[pi.Name] = pi.GetValue(rec, null) == null ? DBNull.Value : pi.GetValue (rec, null); } dtReturn.Rows.Add(dr); } return dtReturn; } --------------------- 作者：jyh_jack 来源：CSDN 原文：https://blog.csdn.net/jyh_jack/article/details/80995537 版权声明：本文为
jyh_jack 原创文章转载
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