DataTable uses Linq for grouping and summarization, and converts the Linq result set into DataTable

DataTable使用Linq进行分组汇总

  var dt1=dt.AsEnumerable();

                    var result1= from r in dt1
                                 group r by new {
     
                                     FPJCABASENUMBER = r.Field<string>("FPJCABASENUMBER"),
                                     FMATERIALNUMBER2 = r.Field<string>("FMATERIALNUMBER2") ,
                                     FINVFBaseQty=r.Field<decimal>("FINVFBaseQty"),
                                     FSAFESTOCK = r.Field<decimal>("FSAFESTOCK"),
                                     //FMUSTQTY = r.Field<decimal>("FMUSTQTY"),
                                     //FQUELIAO = r.Field<decimal>("FQUELIAO"),
                                     //FPOORECEIVEQTY = r.Field<decimal>("FPOORECEIVEQTY"),
                                     //FTPINSTOCKFQTY = r.Field<decimal>("FTPINSTOCKFQTY"),
                                     //FPOPRENOSTOCKQTY = r.Field<decimal>("FPOPRENOSTOCKQTY"),
                                     //FTPMEFQTY = r.Field<decimal>("FTPMEFQTY"),

                                 }
                                 into m
                                 select new
                                 {
    
                                     
                                     FPJCABASENUMBER = m.Key.FPJCABASENUMBER,
                                     FMATERIALNUMBER2 = m.Key.FMATERIALNUMBER2,
                                     FINVFBaseQty = m.Key.FINVFBaseQty,
                                     FSAFESTOCK = m.Key.FSAFESTOCK,
                                     FMUSTQTY = m.Sum(x=>x.Field<decimal>("FMUSTQTY")),
                                     FQUELIAO = m.Sum(x=>x.Field<decimal>("FQUELIAO")),
                                     FPOORECEIVEQTY = m.Sum(x=>x.Field<decimal>("FPOORECEIVEQTY")),
                                     FTPINSTOCKFQTY = m.Sum(x=>x.Field<decimal>("FTPINSTOCKFQTY")),
                                     FPOPRENOSTOCKQTY = m.Sum(x=>x.Field<decimal>("FPOPRENOSTOCKQTY")),
                                     FTPMEFQTY = m.Sum(x=>x.Field<decimal>("FTPMEFQTY")),
                                 };

                    var resultTable = LINQToDataTable(result1);

将Linq结果集转化为DataTable

        /// <summary>
        /// 将IEnumerable<T>类型的集合转换为DataTable类型 
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="varlist"></param>
        /// <returns></returns>
        public DataTable LINQToDataTable<T>(IEnumerable<T> varlist)
        {
       //定义要返回的DataTable对象
            DataTable dtReturn = new DataTable();
            // An array of property information that holds the column collection
            PropertyInfo[] oProps = null;
            if (varlist == null) return dtReturn;//安全性检查
                                                 //循环遍历集合,Use reflection to get property information of a type
            foreach (T rec in varlist)
            {
    
                //使用反射获取T类型的属性信息,返回一个PropertyInfo类型的集合
                if (oProps == null)
                {
    
                    oProps = ((Type)rec.GetType()).GetProperties();
                    //循环PropertyInfo数组
                    foreach (PropertyInfo pi in oProps)
                    {
    
                        Type colType = pi.PropertyType;//得到属性的类型
                                                       //If the property is a generic type
                        if ((colType.IsGenericType) && (colType.GetGenericTypeDefinition()
                        == typeof(Nullable<>)))
                        {
       //获取泛型类型的参数
                            colType = colType.GetGenericArguments()[0];
                        }
                        //Take the property name of the type with the property type asDataTable的列数据
                        dtReturn.Columns.Add(new DataColumn(pi.Name, colType));
                    }
                }
                //Create a new one to add toDataTable中的DataRow对象
                DataRow dr = dtReturn.NewRow();
                //Loop through the property collection
                foreach (PropertyInfo pi in oProps)
                {
       //为DataRowThe specified column assignment in 
                    dr[pi.Name] = pi.GetValue(rec, null) == null ?
                        DBNull.Value : pi.GetValue(rec, null);
                }
                //will have the resulting value ofDataRow添加到DataTable集合中
                dtReturn.Rows.Add(dr);
            }
            return dtReturn;//返回DataTable对象
        }