ASP.NET VB，如何限制文件类型上传？

Question

我有一个子上传文件。如何限制可以上传的文件类型？我不希望用户能够上传.exe、.dll、.ini 文件。现在可以上传任何文件。

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    If FileUpload1.HasFile Then
        Try
            FileUpload1.SaveAs("C:\Uploads\" & _
                FileUpload1.FileName)
            Label1.Text = "File name: " & _
                FileUpload1.PostedFile.FileName & "<br>" & _
                "File Size: " & _
                FileUpload1.PostedFile.ContentLength & "<br>" & _
                "Content type: " & _
                FileUpload1.PostedFile.ContentType & "<br>" & _
                "Location Saved: C:\Uploads\" & _
                FileUpload1.FileName
        Catch ex As Exception
            Label1.Text = "ERROR: " & ex.Message.ToString()
        End Try
    Else
        Label1.Text = "You have not specified a file."
    End If
End Sub

Answer 1

    If FileUpload1.HasFile Then
      Try
        if FileUpload1.FileName.ToLower().Contains(".exe") or FileUpload1.FileName.ToLower().Contains(".dll")  or FileUpload1.FileName.ToLower().Contains(".ini") 
        ' show your alert here stating this type of files are not allowed
        return
        End if
        FileUpload1.SaveAs("C:\Uploads\" & _
            FileUpload1.FileName)
        Label1.Text = "File name: " & _
            FileUpload1.PostedFile.FileName & "<br>" & _
            "File Size: " & _
            FileUpload1.PostedFile.ContentLength & "<br>" & _
            "Content type: " & _
            FileUpload1.PostedFile.ContentType & "<br>" & _
            "Location Saved: C:\Uploads\" & _
            FileUpload1.FileName
      Catch ex As Exception
            Label1.Text = "ERROR: " & ex.Message.ToString()
      End Try
      Else
            Label1.Text = "You have not specified a file."
      End If

But, I would suggest you client side check will be better too.