int ctr, len;
string gee;
t = kalliskaBillingDataSet.Tables["DealerDetail"];
len = t.Rows.Count - 1;
r = t.Rows[len];
string id = r["DealerID"].ToString();
gee = id.Substring(1, 3);
ctr = int.Parse(gee);
行中的输入字符串格式不正确::
ctr = int.Parse(gee);