使用 HTML POST 将图像上传到网络服务器

Question

我正在尝试制作一个屏幕捕获程序，然后将其直接上传到其中一台服务器。不幸的是，我尝试的所有方法要么给我错误，要么根本没有解决。

Private Sub Form1_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseUp
    Form2.Hide()
    Me.Hide()
    Dim bounds As Form2
    Dim screenshot As System.Drawing.Bitmap
    Dim graph As Graphics
    bounds = Form2
    screenshot = New System.Drawing.Bitmap(bounds.Width, bounds.Height, System.Drawing.Imaging.PixelFormat.Format32bppRgb)
    graph = Graphics.FromImage(screenshot)
    graph.CopyFromScreen(Form2.Bounds.X, Form2.Bounds.Y, 0, 0, bounds.Size, CopyPixelOperation.SourceCopy)
    Form2.BackgroundImage = screenshot
    Using sendto As New Net.WebClient
        Dim param As New Specialized.NameValueCollection
        param.Add("userfile", screenshot)
        Dim response_bytes = sendto.UploadValues("http://www.directimg.eu/index.php", "POST", param)
        Dim response_body = (New Text.UTF8Encoding).GetString(response_bytes)
    End Using
    Me.Close()
End Sub

这是我当前的代码，不幸的是它不起作用，因为 "screenshot" 需要是一个字符串。希望能帮到我！

谢谢。

Answer 1

要在 POST 数据中发送图像，您需要将它们转换为 Base64 字符串。但首先你必须得到图像字节。这是一个示例，我已根据需要进行了修改，因为我没有您的表格，但您应该可以遵循它：

Imports System.Drawing
Imports System.IO

Module Module1

Sub Main()
    Dim screenshot As System.Drawing.Bitmap
    Dim graph As Graphics

    screenshot = New System.Drawing.Bitmap(400, 400, System.Drawing.Imaging.PixelFormat.Format32bppRgb)
    graph = Graphics.FromImage(screenshot)

    graph.CopyFromScreen(20, 500, 0, 0, New Size(400, 400), CopyPixelOperation.SourceCopy)

    Dim ms As MemoryStream = New MemoryStream()
    screenshot.Save(ms, System.Drawing.Imaging.ImageFormat.Png)

    'screenshot.Save("c:\deleteme\screenshot.png")

    Dim imgBytes As Byte() = ms.ToArray()
    Dim imgStr As String = System.Convert.ToBase64String(imgBytes)

    Using sendto As New Net.WebClient
        Dim param As New Specialized.NameValueCollection
        param.Add("userfile", imgStr)
        Dim response_bytes = sendto.UploadValues("http://www.directimg.eu/index.php", "POST", param)
        Dim response_body = (New System.Text.UTF8Encoding).GetString(response_bytes)
    End Using

End Sub

End Module

使用 HTML POST 将图像上传到网络服务器

Upload an image to webserver using HTML POST

html

vb.net

post