equivalent of vbCrLf in c#

You are looking for System.Environment.NewLine.

On Windows, this is equivalent to \r\n though it could be different under another .NET implementation, such as Mono on Linux, for example.

I typically abbreviate so that I can use several places in my code. Near the top, do something like this:

 string nl = System.Environment.NewLine;

Then I can just use "nl" instead of the full qualification everywhere when constructing strings.

AccountList.Split("\r\n");