sendkeys to open dialog that open from button click in a webbrowser

Question

I use webcontrol to open a webpage, after page is loaded in the webBrowser1_DocumentCompleted method I use the following code to click a button that opens an Open dialog.

webBrowser1.Document.GetElementById("CsvFile").InvokeMember("click");

How can I control (sendkeys, click the Open button etc.) the dialog from code ??