在VB中实现单个文件上传到文件夹可以使用以下代码：
Imports System.IO
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim openFileDialog1 As New OpenFileDialog()
openFileDialog1.Filter = "All files (*.*)|*.*"
openFileDialog1.Multiselect = False
If openFileDialog1.ShowDialog() = DialogResult.OK Then
Dim selectedFile As String = openFileDialog1.FileName
Dim folderPath As String = "C:\YourFolderPath\" ' 指定文件夹路径
Dim fileName As String = Path.GetFileName(selectedFile)
Dim destinationFile As String = Path.Combine(folderPath, fileName)
File.Copy(selectedFile, destinationFile)
MessageBox.Show("File uploaded successfully.")
End If
End Sub
End Class
在上面的代码中，首先创建一个OpenFileDialog对象来选择要上传的文件，然后获取所选文件的路径并指定文件夹路径。接着使用File.Copy方法将选择的文件复制到指定的文件夹中，并显示上传成功的消息框。
