case "变量1“dim dt as datatable
Dim b As New GroupTableBuilder("统计表",DataTables("Tran"))
b.Groups.AddDef("Language")
b.Totals.AddDef("TNumber",AggregateEnum.Count,"记录数")
b.FromServer = True
If Tables.Contains("统计表")=False Then
dt = b.Build(False)
End If
Dim trv As WinForm.TreeView = e.Form.Controls("TreeView1")
trv.CreateTree(dt, "Language")
end select
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上面代码中如果表不存在则生成表没问题,但如果表存在了就报错”未将对象引用设置到对象的实例。“ 是不是其中这一段我写的不对?应该怎样处理一下?
If Tables.Contains("统计表")=False Then
dt = b.Build(False)
End If