将linq查询结果转换为数据表C#

Question

我想将linq查询结果转换为datatable,以便我可以将数据表分配给GridView以在asp页面上显示它.

但是我无法将结果转换为datatable,我没有在我的代码中获取CopyToTable()方法.

请告诉我这里做错了什么？

 var gradeData = (from data in oAngieCtxt.prc_ShopInstanceCustomersData(Convert.ToInt32(this.ShopInstanceID), 10000, false)
                     .Where( row => row.RecievedPoints != "n/a" )
                    .GroupBy(row => new { row.Name })
                    .Select(g => new GroupedPoints()
                    {
                        Name = g.Key.Name,
                        TotalPoints = g.Sum(x => Convert.ToDouble(x.RecievedPoints) * (x.Weightage.ToString() == "0.00" ? 1 : Convert.ToDouble(x.Weightage)))
                    })
                     select data).ToList();

 DataTable dt = gradeData --gradeData.CopyToTable()

注意:可以使用对dataextentions dll的引用.

提前致谢

Answer 1

首先声明一个新的 DataTable 并添加列，在此：

DataTable dt = new DataTable();
dt.Columns.Add("FirstName");
dt.Columns.Add("LastName");
DataRow row = null;

现在我简单地遍历查询并填充一个数据表：

foreach (var rowObj in query)
{
    row = dt.NewRow();
    dt.Rows.Add(rowObj.FirstName, rowObj.LastName);
}

Answer 2

你应该得到DataTableExtensions.CopyToDataTable

删除ToList().

CopyToDataTable是一个IEnumerable<DataRow>扩展(不幸的是).

下面有一个自定义CopyToDataTable扩展方法的解决方案.

var gradeData = (from data in oAngieCtxt.prc_ShopInstanceCustomersData(
                 Convert.ToInt32(this.ShopInstanceID), 10000, false)
                .Where( row => row.RecievedPoints != "n/a" )
                .GroupBy(row => new { row.Name })
                .Select(g => new
                {
                    Name = g.Key.Name,
                    TotalPoints = g.Sum(x => Convert.ToDouble(x.RecievedPoints) 
                    * (x.Weightage.ToString() == "0.00" ? 1 
                      : Convert.ToDouble(x.Weightage)))
                })
                 select data);

var dt = gradeData.CopyToDataTable();

编辑:

这是CopyToDataTable的一个更有用的实现DataRow没有类型约束.

  public static class DataSetLinqOperators
  {
    public static DataTable CopyToDataTable<T>(this IEnumerable<T> source)
    {
        //you find the ObjectShredder implementation on the blog wich was linked.
        return new ObjectShredder<T>().Shred(source, null, null);
    }

    public static DataTable CopyToDataTable<T>(this IEnumerable<T> source, 
                                     DataTable table, LoadOption? options)
    {
        return new ObjectShredder<T>().Shred(source, table, options);
    }

  }