1、2

Dim dtb As New DataTableBuilder("表E")
dtb.AddDef("项目", Gettype(String), 32)
For Each v As String In DataTables("表C").GetValues("第一列", "", "_Sortkey")
    dtb.AddDef(v, Gettype(String))
Next
dtb.Build()

For Each dc As DataCol In DataTables("表C").datacols
    If dc.name <> "第一列" Then
        Dim dr1 As DataRow = DataTables("表E").AddNew()
        dr1("项目") = dc.name
        For Each dr As DataRow In DataTables("表C").datarows
            dr1(dr("第一列")) = dr(dc.name)
        Next
    End If
Next

MainTable = Tables("表E")

3、你把临时表导出，然后导入即可。

3、

Dim Builder As New ADOXBuilder
Builder.Open()

If DataTables.Contains("表E") Then
    If DataTables("表E").Type <> 5 Then
        With Builder
            .DeleteTable("表E")
        End With
    End If
    DataTables.unload("表E")
End If

Dim tbl = Builder.NewTable("表E") \'创建表
tbl.AddColumn("项目" ,ADOXType.String, 32)
For Each v As String In DataTables("表C").GetValues("第一列", "", "_Sortkey")
    tbl.AddColumn("a" & v,ADOXType.String)
Next
Builder.AddTable(tbl) \'增加表
Builder.Close()

DataTables.load("表E")
For Each dc As DataCol In DataTables("表C").datacols
    If dc.name <> "第一列" Then
        Dim dr1 As DataRow = DataTables("表E").AddNew()
        dr1("项目") = dc.name
        For Each dr As DataRow In DataTables("表C").datarows
            dr1("a" & dr("第一列")) = dr(dc.name)
        Next
    End If
Next

MainTable = Tables("表E")