Matt J. Wilson

So you have a WebBrowser object in .NET that you would like to use to automatically post a file to a given location?  You can probably figure out how to set values on this page:

<input type="text" name="myTextField">

// Update myTextField with a value
webBrowser.Document.All["myTextField"].SetAttribute("value", "I set your value");

But how do you update this?

<input type="file" name="myFileField">

You can’t simply use the SetAttribute function, as there is no attribute to correctly set; this was done intentionally to prevent users from using shady Javascript to automatically capture and send files from a page.  So how do you do it?  Something even more shady:

HtmlElement element = webBrowser.Document.GetElementById("myFileField");
element.Focus();
System.Threading.Thread.Sleep(1000);

// Perform SendKeys to fake the browser into setting the file name
SendKeys.SendWait(@"C:\Path To My File\test.txt");
SendKeys.Flush();

I hope that Google picks this up and saves someone else the thirty minutes worth of their life that I wasted attempting to figure out a solution.