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。
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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
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
Dim MyClient As WebClient = New WebClient
Dim MyReader As New System.IO.StreamReader(MyClient.OpenRead(url), System.Text.Encoding.Default) '定义新的文件流并读取网页文件数据，url表示需要打开的网页地址
Dim longTxt As String = MyReader.ReadToEnd 'longtxt存储了网页的源码
MyReader.Close()
很简单的。这个最基本的了。
就是从数据库表中 找出一个记录，名称和密码都和你输入的一样的记录，就表示登陆成功。
简单的思路：（密码也没有加密等）
dim dt As New DataTable
dim cmd As New SqlCommand
With cmd
.CommandText = "Select * From Users Where UserName=@UserName and UserPwd=@UserPwd"
.Parameters.Add(New SqlClient.SqlParameter("@UserName", "=你输入的用户名TextBox1.Text"))
.Parameters.Add(New SqlClient.SqlParameter("@strColorNo", "=你输入的密码TextBox2.Text"))
End With
dt =SqlHelper.GetDatatable(cmd)
if dt.rows.count0 then
msgbox "ok"
else
msgbox "error"
end if