vb.net串口源代码,vb 串口

求vb.net的源代码，最好说明其解决问题，越多越好，满意加50分。

下面这段代码，是我用来计算每个月存500元进银行，连续30年，最后连本带利能有多少钱。这里面涉及复利计算。界面中右边的文本框用来输出每一次计算的结果。

  Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

      Dim nianxian As Integer '年限变量

      Dim dingcun As Integer '定存变量

      Dim fuli_big As Long '大复利

      Dim fuli_small As Long '小复利

      Dim i As Integer '循环变量

      Dim DATAstring As String '数据字符串

      nianxian = Val(年限_TextBox.Text)

      dingcun = Val(定存_TextBox.Text)

      DATAstring = ""

      For i = 1 To nianxian

          fuli_small = dingcun * (1 + 0.1875)

          dingcun = fuli_small

          fuli_big = fuli_big + fuli_small

          DATAstring = DATAstring + "[" + Trim(Str(i)) + "]" + Str(fuli_big) + Chr(13) + Chr(10)

          'DATAstring = DATAstring + "[" + Trim(Str(i)) + "]" + Str(fuli_small) + Chr(13) + Chr(10)

      Next

      'fuli_big = fuli_small

      TextBox1.Text = DATAstring

      结果_TextBox.Text = Str(fuli_big) + "元"

  End Sub

如何用vb.net获得网页的源代码

Dim url As String=" 网址"

Dim httpReq As System.Net.HttpWebRequest

Dim httpResp As System.Net.HttpWebResponse

Dim httpURL As New System.Uri(url)

httpReq = CType(WebRequest.Create(httpURL), HttpWebRequest)

httpReq.Method = "GET"

httpResp = CType(httpReq.GetResponse(), HttpWebResponse)

httpReq.KeepAlive = False ' 获取或设置一个值，该值指示是否与

Internet资源建立持久连接。

Dim reader As StreamReader = _

New StreamReader(httpResp.GetResponseStream,

System.Text.Encoding.GetEncoding(-0))

Dim respHTML As String = reader.ReadToEnd() 'respHTML就是网页源代码

怎样在vb中自动检测到可用串口号的具体程序代码

j = 0

For i = 1 To 16 Step 1

If comISP.PortOpen = True Then '先关闭串口

comISP.PortOpen = False

End If

comISP.CommPort = i

On Error Resume Next '说明当一个运行时错误发生时，控件转到紧接着发生错误的语句之后的语句，并在此继续运行。访问对象时要使用这种形式而不使用 On Error GoTo。

comISP.PortOpen = True

If Err.Number 8002 Then '无效的串口号。这样可以检测到虚拟串口，如果用Err.Number = 0的话检测不到虚拟串口

If j = 0 Then

j = i

End If

cboPort.AddItem "COM" i '生成串口选择列表

End If

comISP.PortOpen = False

Next i

If j = 1 Then

cboPort.Text = "COM" j '自动打开可用的最小串口号

comISP.CommPort = j

comISP.PortOpen = True

cmdOpenCom.Caption = "关闭串口"

shpCOM.FillColor = vbGreen

If Err.Number = 8005 Then '串口已打开,vbExclamation '

comISP.PortOpen = False

cboPort.Text = ""

cmdOpenCom.Caption = "打开串口"

shpCOM.FillColor = vbRed

End If

End If