vb 字符串组成过程函数名调用,该怎么解决

vb 字符串组成过程函数名调用
代码类似下边

dim aa as string
aa="zhu"
call aa
sub zhu()
msgbox"试验提示"
end if 

正常调用是call zhu

可是我现在用了字符串
请问怎么转换下可以调用字符串组成的函数名zhu

[解决办法]

VB code

'form1Option ExplicitPublic Sub zhu()    MsgBox "试验提示"End SubPrivate Sub Command1_Click()    Dim aa As String    aa = "zhu"    CallByName Me, aa, VbMethodEnd Sub