C#中怎样把一个字符串转换成字符形数组？

ToCharArray()

转化为文件名的字符串数组
{
string a = "1.jpg2.jpg3.jpg4.jpg";
string t = "jpg";string tt = "jpg ";
string b = a.Replace(t, tt);
string[] c = b.Split(' ');
for (int i = 0; i < c.Length; i++)
{
Console.WriteLine(c[i]);
}

string question_id = "[sss,dddd,ffff,eee,rrr]"
string[] questionarr = question_id.Split(',');