So, first, let me make some assumptions: I'll assume that you are female and the colleagues/contacts are male. I'll further assume you're in a "western" - ie, American or European - culture. If these are incorrect assumptions, you can ignore the "second".
Second, the average American or European is more likely to strike up a romantic relationship at work than anywhere else (in person, anyway - internet dating is probably on a par). Outside of work, the opportunities to strike up a conversation with a woman are few, and often frowned upon. If your industry is tech-related, then sadly we have a dearth of female colleagues and contacts, so the opportunities in work are few and far between as well. Given all this, women in tech get more romantic attention than they probably want, but for the majority of men in the industry, it's simply a rare opportunity to find a potential girlfriend without having to approach a woman entirely cold - and that in turn is heavily frowned upon.
I say all this not because it's okay for dozens of men to hit on you, but in order that you understand that men trying to shift a relationship from purely professional to something else is not in itself a malaise of the industry, it's just a byproduct of a combination of social pressures and an unfortunate minority of women in the industry.
So, you are, unfortunately, going to get more attention than you want - and the individual men doing the "hitting" are going to be blissfully unaware that they're doing anything to annoy you. Men are rarely in the situation of being the only man in a sea of women, constantly being hit on, and would probably think it sounded quite good - until they considered the reality.
And so we move onto thirdly... What can you do about it? I can't give much advice - you'd be amazed, but men hardly ever hit on me - but I can tell you a few things to do.
If you want to keep things professional, then keep things professional. Cool, calm, polite rejection is fine. Trust me, we're men in tech, we're expecting it.
If a guy doesn't take no for an answer, or is aggressive, or in any other way is behaving in a way that would individually be unacceptable, then burn that bridge. Ideally with him on it.
But... try not to lash out at the fourth (or fifth, or ninetieth) guy to politely ask you if you'd like a drink after work. Honestly, he won't have thought about the previous three (or four, or eighty-nine). He'll probably be thoroughly ashamed if he knew. It might even be worth telling him, politely, that he's the sixth one this week, and it might even be flattering if it weren't just that you're the only girl in the department. [Adjust to fit].
Keep a "contemporaneous account", even if it seems innocent at first. Emailing yourself is a good one, but use a gmail account or something else you clearly don't control. Then should it have to involve HR, or even courts, then you have admissible, actionable evidence.
Explaining the situation to (non-hitting) colleagues helps. Men are not devoid of empathy - no matter how many times we get told we should be - and your team members will look out for you. If they don't, they're not worth working with.
As I point out, however, I'm a man, and so thankfully haven't been in your situation. Good luck.
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So, first, let me make some assumptions: I'll assume that you are female and the colleagues/contacts are male. I'll further assume you're in a "western" - ie, American or European - culture. If these are incorrect assumptions, you can ignore the "second".
Second, the average American or European is more likely to strike up a romantic relationship at work than anywhere else (in person, anyway - internet dating is probably on a par). Outside of work, the opportunities to strike up a conversation with a woman are few, and often frowned upon. If your industry is tech-related, then sadly we have a dearth of female colleagues and contacts, so the opportunities in work are few and far between as well. Given all this, women in tech get more romantic attention than they probably want, but for the majority of men in the industry, it's simply a rare opportunity to find a potential girlfriend without having to approach a woman entirely cold - and that in turn is heavily frowned upon.
I say all this not because it's okay for dozens of men to hit on you, but in order that you understand that men trying to shift a relationship from purely professional to something else is not in itself a malaise of the industry, it's just a byproduct of a combination of social pressures and an unfortunate minority of women in the industry.
So, you are, unfortunately, going to get more attention than you want - and the individual men doing the "hitting" are going to be blissfully unaware that they're doing anything to annoy you. Men are rarely in the situation of being the only man in a sea of women, constantly being hit on, and would probably think it sounded quite good - until they considered the reality.
And so we move onto thirdly... What can you do about it? I can't give much advice - you'd be amazed, but men hardly ever hit on me - but I can tell you a few things to do.
As I point out, however, I'm a man, and so thankfully haven't been in your situation. Good luck.