比较DART中第三个列表中的两个嵌套列表和商店差异

Question

我有两个salesorderheader列表（让我们在之前和之后打电话），需要检查salessqty字段是否有差异。如果发现差异，则将其记录在第三个列表中（我们称之为差异）。据说需要比较的项目将处于相同的索引中，但是要谨慎，我希望salesid和itemrecid在计算差异之前匹配两个列表之间。

salesorderhheader.dart

class salesOrderHeader {
  String? salesId = "";
  List<SalesOrderLine>? salesOrderLine;

salesorderline.dart

class salesOrderLine {
  String salesId = "";
  int itemRecId = "";
  String itemId = "";
  String itemName = "";
  double salesQty = 0.0;

Answer 1

这就是我设法做的，似乎有效，但我想知道是否有更好的答案。

for (var i = 0; i < Before!.length; i++) { 
    for (var j = i; j < Before![i].salesOrderLine!.length; j++) { 
      for (var k = 0; k < After.length; k++) { 
        for (var l = k; l < After[i].salesOrderLine!.length; l++) { 
          if (Before![i].salesOrderLine![j].salesId == After![k].salesOrderLine![l].salesId && Before![i].salesOrderLine![j].itemRecId == After![k].salesOrderLine![l].itemRecId ){
            if (Before![i].salesOrderLine![j].salesQty != After![k].salesOrderLine![l].salesQty){             

              double newQty = Before![i].salesOrderLine![j].salesQty - After![k].salesOrderLine![l].salesQty;

              List<SalesOrderLine> Difference = [];
              Difference.add(new SalesOrderLine(salesId: After![k].salesOrderLine![l].salesId,
                                                    itemRecId: After![k].salesOrderLine![l].itemRecId,
                                                    itemId: After![k].salesOrderLine![l].itemId,
                                                    itemName: After![k].salesOrderLine![l].itemName,
                                                    salesQty: newQty));
              
            }
          }
        }
      }
    }
  }