DEMO:
//正则表达式匹配纯中文和字母
bool isPass = System.Text.RegularExpressions.Regex.IsMatch(inputString, @"^[\u4e00-\u9fa5A-Za-z]+$");
//加上中英文标点符号
isPass = System.Text.RegularExpressions.Regex.IsMatch(inputString, @"^[\、\，\。\；\：\‘\’\！\,\.\;\:\'\!\u3002\uff1b\uff0c\uff1a\u201c\u201d\uff08\uff09\u3001\uff1f\u300a\u300b\u4e00-\u9fa5A-Za-z]+$");
if (isPass == false)
{
}