LINQ：查询返回空对象的列表

Question

I have a query that 'selects' object of a type:

Dim l as IList(Of Foo) = (From dataRow As DataRow In table.Select()
                          Where CStr(dataRow("Column1")) = "A"
                          Select New Foo(CStr(dataRow("Column1")), _
                                         CStr(dataRow("Column2")))).ToList()

What's happening is that if i set a break-point to the constructor of Foo and step, the constructor is hit and the parameters are loaded with the arguments. However, l has empty Foo objects (the members in every object are Nothing ). What could be happening here?

Answer 1

Change your query to :

Dim l as IList(Of Foo) = (From dataRow As DataRow In table..AsEnumerable()
                          Where datarow.Field(of String)("Column1") = "A" 
                          Select New Foo(datarow.Field(of String)("Column1"), _
                                         datarow.Field(of String)("Column1"))).ToList()

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