Can you read the binary data for the file in Visual Studio? If so, look for a line starting with '%%Creator'. The rest of the line should be the application and version info (at least it is with the various EPS files I checked; don't have CorelDraw to test)
OK I understand where you are going.
Now here is one issue.
I can open 1 EPS file in Acrobat and in the properties it shows Application is CorelDraw x5.
Looking at the binary it shows Creator as
/Producer <feff0043006f00720065006c002000500044004600200045006e00670069006e006500200056006500720073 0069006f006e002000310035002e0032002e0030002e003600360031>
This file would be a problem since I can't get the Creator.
I can open other .EPS files in Acrobat in the properties it shows Application is Illustrator.
Looking at the binary it shows Create as:
<xmp:CreatorTool>Adobe Illustrator CS6 (Macintosh)</xmp:CreatorTool>
This file would not be a problem at all.
And opening a CorelDraw file (.CDR) is all binary and no text that is understandable.
Don't look for 'Creator', look for '%%Creator' -include the %% in the search (there may be several lines which include 'Creator', but should only be one that starts with '%%Creator'). Again, not sure if the CorelDraw files conform to this or not.
Edit: that assumption may not be accurate, there may be multiple lines which start with %%Creator - but those lines should contain the application info.