trigger file dialog programmatically?

To trigger another component or element programmatically I can use refbut I got an error of photoUploadDropAreaElement is not a function using below code.

```
triggerUploadDialog(){
this.photoUploadDropAreaElement.click(); // doesn't work?

console.log(this.photoUploadDropAreaElement);
}

render() {
return(

http://stackoverflow.com/questions/43295907/trigger-react-dropzone-with-ref-doesnt-work

The issue identifies triggerUploadDialog, render, and DropzoneComponent but no repository files or tests. Start by reproducing the ref assignment and click call from the example, then trace the component entry point to determine whether the programmatic dialog trigger is supported. Done means the intended behavior is confirmed and either works reliably or is clearly documented.

Written by the indexing model from the issue text.