主题：[求助]模拟关联

老师，下面代码不能提取字符。

datarowadding

If CurrentTable.Name = "BIOS_Table3" Then '如果当前表是模拟的关联表
    Dim r As Row = Tables("BIOS_Table1").Current    
    If r IsNot Nothing Then        
        Dim str As String = r("主菜单")
        Dim ary = str.split(" ")
        Dim nstr As String = ""
        For Each s As String In ary
            nstr &= left(s,  1)
        Next
        e.DataRow("类型") = nstr
    End If
End If