VB.NET 画面PictureBox中显示网络图片的多种方式。

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VB.NET 画面PictureBox中显示网络图片的多种方式。

1.获取网络动态图片的api，设置图片显示。

Dim wr As WebRequest = WebRequest.Create("https://uploadbeta.com/api/pictures/random/?key=BingEverydayWallpaperPicture")

Dim res As WebResponse = wr.GetResponse

Dim bmp As Bitmap = New Bitmap(res.GetResponseStream)

Me.PictureBox1.Image = bmp

2.抓取网页中的图片，下载到本地文件夹，然后再显示。

(因为使用了1的方法，这里是完成部分的代码，里面的方法可以参考使用)

Pic_net.vb

Imports System.IO

Imports System.Net

Imports System.Text.RegularExpressions

Public Class Pic_net

Private Obj As New ArrayList

Public jpg_obj As New ArrayList

Public Function NetGetData(ByVal Url As String, Optional ByVal GetData As String = "") As String

Dim tmp As String = ""

Try

'根据网站链接，获取网页数据。

Dim Request As HttpWebRequest

Request = CType(WebRequest.Create(Url + "?" + GetData), HttpWebRequest)

Request.Method = "GET"

Dim Strm As Stream

Strm = Request.GetResponse().GetResponseStream

Dim Sr As StreamReader = New StreamReader(Strm)

tmp = Sr.ReadToEnd

Catch ex As Exception

MsgBox(ex.Message)

End Try

Return tmp

End Function

Public Function Get_list(ByVal Arr As Object, ByRef tf As Boolean, ByRef XREG As String) As Object

Dim tmp As Object()

Try

'解析出<img>标签。

Dim reg As New Regex("<img\b[^<>]*?\bsrc[\s\t\r\n]*=[\s\t\r\n]*[""']?[\s\t\r\n]*(?<imgUrl>[^\s\t\r\n""'<>]*)[^<>]*?/?[\s\t\r\n]*>")

Dim match As MatchCollection = reg.Matches(CType(Arr, String))

ReDim tmp(match.Count)

If match.Count = 0 Then

tf = False

Else

tf = True

End If

Dim i As Integer = 0

For Each m As Match In match

tmp(i) = m.Groups("imgUrl").Value

i += 1

Application.DoEvents()

Catch ex As Exception

MsgBox(ex.Message)

End Try

Return tmp

End Function

Public Function GET_ZJADD(ByVal xstart As Integer, ByVal xend As Integer) As Boolean

Dim tf As Boolean

Dim tmp As Object()

For i As Integer = xstart To xend

'通过NetGetData方法获取img中的图片url。

tmp = CType(Get_list(NetGetData("网址" & i & "/"), tf, ""), Object())

If tf = True Then

For Each xl As String In tmp

If xl <> Nothing Then

Obj.Add(xl)

End If

jpg_obj = Obj

End If

Application.DoEvents()

Return True

End Function

Public Function FileDown(ByVal URL As String, ByVal saveFile As String) As Boolean

Dim myWebclient As WebClient

Try

'下载图片

myWebclient = New WebClient()

myWebclient.DownloadFileAsync(New Uri(URL), saveFile)

Return True

Catch ex As Exception

Return False

End Try

End Function

End Class

显示图片的代码

Dim strImage As String = Down_pic()

Try

Dim wr As WebRequest = WebRequest.Create(strImage)

Dim res As WebResponse = wr.GetResponse

Dim bmp As New Bitmap(res.GetResponseStream)

'显示图片

Me.PictureBox1.Image = bmp

Catch ex As Exception

Me.PictureBox1.Image = Nothing

End Try

Function Down_pic() As String

Dim pic As New Pic_net

Dim strImage As String

Get_path()

pic.GET_ZJADD(1, 1)

Dim arr As ArrayList = pic.jpg_obj

Dim i As Integer = arr.Count

Dim J As Integer = 1

For Each xl As String In arr

Dim str As String = xl

If InStr(str.ToLower, ".gif") > 0 Then

'下载图片

pic.FileDown(xl, "C:\Users\" & Environment.UserName & "\Desktop\PIC\" & J & ".gif")

ElseIf InStr(str.ToLower, ".jpg") > 0 Then

pic.FileDown(xl, "C:\Users\" & Environment.UserName & "\Desktop\PIC\" & J & ".jpg")

End If

J += 1

Application.DoEvents()

'这里可以从下载的图片选一个显示。

Return strImage

End Function

Function Get_path() As Boolean

'本地路径

Dim path As String = "C:\Users\" & Environment.UserName & "\Desktop\PIC\"

If Directory.Exists(path) = False Then

Directory.CreateDirectory(path)

Return True

Else

Return False

End If

End Function

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原文链接：https://blog.csdn.net/ningyingjun/article/details/108833336

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