vb.net读取流的简单介绍
vb.net读取文件流
dim filename as string = "文件名" Using myfilestream As New FileStream(FileName, FileMode.Open, FileAccess.Read)
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Dim data() As Byte
ReDim data(myfilestream.Length - 1)
myfilestream.Read(data, 0, myfilestream.Length)
myfilestream.Close()
' data是你要的结果,为byte(), End Using
vb.net读取流
Imports System
Imports System.IO
Imports System.TextPublic Class Form2 Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim path As String = "MyTest.txt" Try
If File.Exists(path) Then
File.Delete(path)
End If '写入流
Dim sw As StreamWriter = New StreamWriter(path)
sw.WriteLine("This")
sw.WriteLine("is some text")
sw.WriteLine("to test")
sw.WriteLine("Reading")
sw.Close()
'读取流
'Dim sr As StreamReader = New StreamReader(path) 'Do While sr.Peek() = 0
' 'This is an arbitrary size for this example.
' Dim c(5) As Char
' sr.Read(c, 0, c.Length)
' 'The output will look odd, because
' 'only five characters are read at a time.
' 'MsgBox(c)
'Loop
'sr.Close()
Catch ex As Exception
Console.WriteLine("The process failed: {0}", ex.ToString())
End Try End Sub '读取流
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim path As String = "MyTest.txt" Dim reader As StreamReader = New StreamReader(path)
Dim c(5) As Char
reader.Read(c, 0, c.Length)
MsgBox(c)
reader.Close() End Sub
End Class 解读Read(arrayChar[]()[], Int32, Int32) buffer 类型:arraySystem..::.Char[]()[]
此方法返回时,包含指定的字符数组,该数组的 index 和 (index + count - 1) 之间的值由从当前源中读取的字符替换。 index 类型:System..::.Int32
开始写入的 buffer 的索引。 count 类型:System..::.Int32
最多读取的字符数。
VB.net怎样从网络中逐个读取数据
Public Function webCaptureContent(ByVal mWebsiteUrl As String, ByVal mWebsiteType As Boolean) As String
'启动一次具体的数据采集工作,返回采集到的HTML内容:要求必须输入带://的全地址数据
On Error Resume Next
Dim Str_WebContent As String = "请输入查找网站地址."
Dim wb As WebClient = New WebClient() '//创建一个WebClient实例
If mWebsiteUrl.IndexOf("://") 0 Then
'//获取或设置用于对向 Internet 资源的请求进行身份验证的网络凭据。(可有可无)
wb.Credentials = CredentialCache.DefaultCredentials
'//从资源下载数据并返回字节数组。(加@是因为网址中间有"/"符号)
Dim pagedata As Object = wb.DownloadData(mWebsiteUrl)
'//转换字符
If mWebsiteType Then
Str_WebContent = Encoding.Default.GetString(pagedata)
Else
Str_WebContent = Encoding.UTF8.GetString(pagedata)
End If
End If
Return Str_WebContent '提取出来新闻内容,删除Body前后的多余内容,同时补充上该 Body标记,形成完整的内容 Str_WebContent '
End Function
求VB.NET读取网页内容写法
Imports System.Net
Imports System.IO
Imports System.Text.RegularExpressions
Public Class Form1
Private Sub button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim stream As IO.Stream = WebRequest.Create(UrlAdress).GetResponse().GetResponseStream()
'注意urladress为你上面的网页地址。
Dim sr As StreamReader = New StreamReader(stream, System.Text.Encoding.UTF8)
Label1.Text = Regex.Match(sr.ReadToEnd, "回答采纳率").ToString
'sr。readtoend读取网页流到末尾,即使用正则表达式从网页流中提取“回答采纳率”,赋值给Label1.Text ‘没有则为空
sr.Dispose() '关闭流
End Sub'要提取什么东西用正则表达式最好
End Class
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