由于无益，因为这可能是，AFAIK有没有办法来解决它与泛型。

As unhelpful as this may be, AFAIK there's no way to get around it with generics.

为什么不直接用对象工作？它是一个性能问题？

Why not just work with Object? Is it a performance issue?

Public Shared Function GetQueryStringValue(ByVal queryStringVariable As String, ByVal t As Type) As Object
    Dim queryStringObject As Object = Nothing
    If queryStringVariable <> Nothing Then
        If HttpContext.Current.Request.QueryString(queryStringVariable) IsNot Nothing Then
            queryStringObject = CTypeDynamic(queryStringVariable, t)
        End If
    End If

    Return queryStringObject
End Function