无法连接到mysql数据库C＃

Question

I am trying to connect to my db with C# and query some data.

But i get this error when trying to connect:

{"Fatal error encountered during command execution."}
{"Parameter '?param1' must be defined."}

Code:

checkmsisdn.CommandText = "SELECT name FROM acl where msisdn = ?param1 and passwd = ?param2 and items LIKE (\"%?param3%\")";  //fourth
//try
//{
    sqlConn.Open();
    Reader = checkmsisdn.ExecuteReader();
    checkmsisdn.Parameters.Add(new MySqlParameter("param1", msisdn));
    checkmsisdn.Parameters.Add(new MySqlParameter("param2", passwd));
    checkmsisdn.Parameters.Add(new MySqlParameter("param3", itemno));
//}
//catch 
//{ 
//    Console.WriteLine("Error Connecting to Database\n"); 
//}

while (Reader.Read())
{
    name = (Reader.GetValue(0).ToString());
}

the query will return only one line, the name. am i using the parameters correctly for this query ?

Answer 1

您在添加参数之前调用ExecuteReader() 。