编号和型号的格式不同吧?根据格式不同(比如,字符数不同等条件)
Dim txt As String = Ports("COM6").ReadExisting()
If txt.length = 10 Then Forms("焊接调试检验").Controls("TextBox1").Text = txtElseIf txt.length = 5 Then Forms("焊接调试检验").Controls("TextBox3").Text = txtEnd If