Q:

Do workshop publications hold the same value as conference publications in CS? 

I had missed deadline for a reputable conference (Computer Science).  Now I see that a workshop is being organized with the conference which exactly aligns with my area of research.  The workshop proceedings will be published with the conference proceedings. ( It is the first workshop in this series)
Does a workshop publication holds same value as a conference publication for PhD work, future employment opportunities etc. ? ( I am a PhD Candidate as of now)
Edit

My field is Computer Vision
The conference is ECCV

A:

No, workshops are generally (at least in my area of CS) of much lower value than full conference proceedings. ( Especially when held before a more major conference.)  Even though workshop proceedings are published, they are not always considered archival, and usually are stepping stones to full publications later on.  A workshop is a good place to get feedback on ideas that can then be upgraded to a "full" publication in the future. 
But, I'd strongly advise you to attend the workshop in order to meet and interact with people in the area!  You can get great feedback for taking a weak conference submission and making it a strong accept. 

A:

The answer of that question depends on the quality of your work, how it aligns with the workshop (very well it sounds like) and the conference alternative you are comparing it to.  
Not all workshops and conferences are equal but generally conferences are much more important.  Workshops are often informal and less academically significant.  Ask someone in your field which would be more prestigious in your situation. 
You are asking a hypothetical question without the specifics needed to provide you a quality answer.