https://i.sstatic.net/JGryQ.jpg
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);
Input string was not in a correct format in the line::
ctr = int.Parse(gee);
E00 is not a valid decimal string. You need to parse it as though it's a hex string.
Use something like:
int.Parse(code, System.Globalization.NumberStyles.HexNumber);
Of course, it's possible that the value is not supposed to be hexadecimal, in which case you have an error.
To more gracefully recover from such situations, use int.TryParse(code, out value) instead, and check the return value for true/false, indicating success/failure.
Looking at the screenshot, code was E00, which cannot be converted to an integer.
