c#作业

string a = this.textBox1.Text;
// string [] b=a.Split("\r\n".ToCharArray(),StringSplitOptions.RemoveEmptyEntries);
string[] b = textBox1.Lines;
string maxname = "";
int maxsize = 0;
foreach (string ax in b) {
string[] str = ax.Split('=');
string name = str[0];
string str_code = str[1];
int int_score = Convert.ToInt32(str_code);
if (int_score > maxsize)
{
maxsize = int_score;
}

}
MessageBox.Show(maxsize.ToString());