On the linkbutton Click, I did this code, But the window is not in center of screen. But I think someone here can help me out in this.
Dim url As String = "Popup.aspx"
Dim s As String = "window.open('" & url + "', 'popup_window', 'width=530, height=80, left='+((screen.width - 530) / 2)+', top=' + ((screen.heigth - 80) / 2));"
ClientScript.RegisterStartupScript(Me.GetType(), "script", s, True)
Create a new webform with name Popup.aspx and add File upload and a button in Popup.ASPX
This way I did the way I wanted. But I am new to Dotnet so I don't think this is a good practice because most of the user block pop up windows. I need help in this.