Int32.TryParse，int.Parse，Convert.ToInt32类型转换比较

Convert.ToInt32()在null时不会抛出异常，而是返回0

int.Parse()在null时会抛出异常

Int32.TryParse()不会抛出异常，会返回true或false,如果解析错误返回false，out返回0

从性能上：Int32.TryParse() > int.Parse() > Convert.ToInt32()在.NET1.1下用int.Parse()在.NET2.0下用Int32.TryParse()

实例：

class Program
{
static void Main(string[] args)
{
string str = "1,2,3,4,5,";
Console.WriteLine(str.Substring(0, str.Length - 1));

int nums = 0;
string num = null;
Int32.TryParse(num, out nums);
Console.WriteLine(nums);

/*
int nums = 0;
string num = "12345";
Int32.TryParse(num, out nums);
Console.WriteLine(nums);
*/

nums = Convert.ToInt32(num);

nums = int.Parse(num);
}