The "m_" comes from member, as in member variable.

http://www.structurebydesign.com/Language/Naming.htm

>I don't even remember where we came up with using "m_" ... maybe a holdover from the old FoxPro days with the "m." syntax. <g>
>
>~~Bonnie
>
>
>>>I wouldn't use more than one together.
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>>Neither would I, but apparently a lot of developers have other ideas...
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>>>I was just offering a suggestion, based on what Microsoft is doing.
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>>It's appreciated.
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>>>The most important thing is to be consistent in whatever you choose. It will make reading your code >much easier for other developers.
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>>Yeah, I couldn't agree more (re: being consistent). I actually find it a little disconcerting to not have a definite naming convention worked out yet in .NET. I like the idea of easy to understand visual clues of "what" a variable is. Not just in the sense of what it represents, but its type. I haven't found anything I've been really happy with yet, so I like to hear what other developers have been doing.
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>>>Bonnie suggested using "m_" instead.
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>>We're actually having this same conversation (eg. naming conventions in .NET) over on the WebConnect messageboard. Another person is also using the "m_" prefix. I'll probably meet everyone halfway and prefix it with just an "m".