The included code shows the method openFileDialog1_FileOk_1 the "_1" at the end suggest to me that you had some issues binding the event. Perhaps there was at some point a method openFileDialog1_FileOk caused conflict.
You should check if the method is correctly bound to the event.
For abstract you want to see what method is bound to the event. You can do it from the properties panel, or by checking the form designer file (that is named something .Designer.cs for example: Form1.Designer.cs).
Addendum: Consider adding a break point in the event handler. It will allow you to debug step by step what is happening. Also, it will allow you notice if the event handlers is not being executed at all, which would suggest that the method is NOT correctly bound to the event.
OpenFileDialog Does not open files, it barely select thems and makes the selection available for your application to do whatever your applications is intended to do with those files.
The following is the usage pattern from the MSDN article linked above:
if(openFileDialog1.ShowDialog() == DialogResult.OK)
if ((myStream = openFileDialog1.OpenFile()) != null)
// Insert code to read the stream here.
catch (Exception ex)
"Error: Could not read file from disk. Original error: " + ex.Message