在Linq分组（在多个领域）

我使用linq对一些数据进行分组如下：

var groupedData = from row in salesTable.AsEnumerable() group row by row.Field("InvoiceNum") into grp select grp; 

我想使用row.Field（“InvoiceNum”），row.Field（“InvoiceLineNum”）等一些字段重新组合groupsData ，我不知道linq分组如何与多个字段一起工作？

Answer 1

使用匿名类型对象进行分组。

  var groupedData = from row in salesTable.AsEnumerable() group row by new { InvoiceNum = row.Field("InvoiceNum"), InvoiceLineNum = row.Field("InvoiceLineNum") } into grp select grp; 

或使用命名类

 public class InvoiceGrouping : IEquatable { public string InvoiceNum { get; set; } public string InvoiceLineNum { get; set; } public bool Equals( InvoiceGrouping other ) { return other != null && this.InvoiceNum == other.InvoiceNum && this.InvoiceLineNum == other.InvoiceLineNum; } public override bool Equals( object other ) { return Equals( other as InvoiceGrouping ); } public override int GetHashCode() { unchecked { int hash = 17; hash *= (this.InvoiceNum != null ? 23 + this.InvoiceNum.GetHashCode() : 1); hash *= (this.InvoiceLineNum != null ? 23 + this.InvoiceLineNum.GetHashCode() : 1 ); return hash; } } } var groupedData = from row in salesTable.AsEnumerable() group row by new InvoiceGrouping { InvoiceNum = row.Field("InvoiceNum"), InvoiceLineNum = row.Field("InvoiceLineNum") } into grp select grp;