Question

我正在使用以下格式从Excel工作表中读取数据 -

我需要以下列方式存储数据 -

我试图在Linq lambda表达的帮助下做到这一点，但我想我没有得到这个。

我尝试了什么 -

        DataTable dataTable= ReadExcel();
        var dt = dataTable.AsEnumerable();

        var resultSet = dt.Where(x => !String.IsNullOrEmpty(x.Field<String>("Project_Code")))
                        .GroupBy(x =>
                                    new
                                    {
                                        Month = x.Field<String>("Month"),
                                        ProjectCode = x.Field<String>("Project_Code"),
                                        //change designation columns into row data and then group on it 
                                        //Designation = 
                                    }
                                );
                        //.Select(p =>
                        //            new
                        //            {
                        //                Month= p.d
                        //            }
                        //        );`

Answer 1

我会使用带有预定义指定名称的ToDictionary：

private static readonly string[] designationNames = {"PA","A","SA","M","SM","CON"};
void Function()
{
    /* ... */
    var resultSet = dt.AsEnumerable().Where(x => !String.IsNullOrEmpty(x.Field<String>("Project_Code")))
            .Select(x =>
                new
                {
                    Month = x.Field<String>("Month"),
                    ProjectCode = x.Field<String>("Project_Code"),
                    Designations = designationNames.ToDictionary(d => d, d => x.Field<int>(d))
                }
            );
}

这是规范化版本。如果你想要它变平，请使用：

private static readonly string[] designationNames = {"PA","A","SA","M","SM","CON"};

void Function()
{
    /* ... */
    var resultSet = dt.AsEnumerable().Where(x => !String.IsNullOrEmpty(x.Field<String>("Project_Code")))
        .Select(x =>
            designationNames.Select(
                d =>
                    new
                    {
                        Month = x.Field<String>("Month"),
                        ProjectCode = x.Field<String>("Project_Code"),
                        Designation = d,
                        Count = x.Field<int>(d)
                    }
            )
        ).SelectMany(x => x).ToList();
}

如果类型不总是int，那么您可能希望使用x.Field<String>(d)来检查有效性。

Lambda表达式用于Unpivoting DataTable

1 个答案: