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我在数据表中使用VB中的LINQ来过滤我的结果。GroupBy和数据表上的总和
m_oDataTable.Columns.Add("Name1", GetType(String))
m_oDataTable.Columns.Add("Name2", GetType(String))
m_oDataTable.Columns.Add("Time", GetType(Double))
我试图通过Name1
或Name2
基于用户选择来过滤数据表。
groupBy = "Name1"
'groupBy = "Name2"
我我的分组数据,但我无法Sum
所需的字段。
Dim test = From tab In m_oDataTable.AsEnumerable()
Group tab By groupDt = tab.Field(Of String)(groupBy) Into Group
Select Group
'Getting Error
Dim test2 = From tab In m_oDataTable.AsEnumerable()
Group tab By groupDt = tab.Field(Of String)(groupBy) Into Group
Select New With
{
.Grp = Key, ' Error in this line(Key is a type, cannot be used as a expression)
.Sum = Group.Sum(Function(r) Double.Parse(r.Item("Time").ToString()))
}
我在c#中试过并得到了期望的结果。但有没有运气与VB :(
var test = from tab in m_oDataTable.AsEnumerable()
group tab by tab.Field<string>(groupBy)
into groupDt
select new
{
Group = groupDt.Key,
Sum = groupDt.Sum(r => double.Parse(r["Time"].ToString()))
};
如何在VB中实现这一目标?