http://stackoverflow.com/questions/4208231/visual-studio-adding-space-after-if-statements
In the Visual Studio options, under Text Editor / C# / Formatting / Spacing, in the "Set other spacing options" part, there's an option for "Insert space after keywords in control flow statements".
I suspect you'll find you've got that checked, and you don't want it to be. (I have it checked deliberately :)
如果安装了Resharper，还需要再Resharper里面另外设置