VB.NET发送表单发布数据，就像在浏览器中使用文本和文件一样

Imports System.Net.Http
Imports System.Net.Http.Headers

Public Class FormSubmitter
    Public Async Sub SubmitForm()
        Using client As New HttpClient()
            Dim formContent As New MultipartFormDataContent()

            ' 添加文本字段
            formContent.Add(New StringContent("文本字段的值"), "字段名称")

            ' 添加文件
            Dim fileContent As New ByteArrayContent(File.ReadAllBytes("文件路径"))
            fileContent.Headers.ContentType = MediaTypeHeaderValue.Parse("文件类型")
            formContent.Add(fileContent, "文件字段名称", "文件名")

            ' 发送POST请求
            Dim response As HttpResponseMessage = Await client.PostAsync("目标URL", formContent)

            ' 处理响应
            If response.IsSuccessStatusCode Then
                ' 请求成功
                Dim responseContent As String = Await response.Content.ReadAsStringAsync()
                Console.WriteLine("响应内容：" & responseContent)
            Else
                ' 请求失败
                Console.WriteLine("请求失败：" & response.StatusCode)
            End If
        End Using
    End Sub
End Class