mysql参数化查询语句问题
部分代码如下：
using (MySqlConnection conn = new MySqlConnection(connectionString))
{
conn.Open();
MySqlCommand cmd = new MySqlCommand();
cmd.Connection = conn;
MySqlTransaction ts = conn.BeginTransaction();
try
{
for (int i = 0; i < dt.Rows.Count; i++)
{
cmd.Parameters.AddWithValue("？PrimaryID",dt.Rows[i][1]);
cmd.CommandText = "select * from infomine_bulletin where PrimaryID=？PrimaryID";
object ob = cmd.ExecuteScalar();
返回的Ob为空，但我确实在infomine_bulletin表中能够查询到此条数据，console.writeline(cmd.Parameters["PrimaryID"].value)确实已经赋值，select语句失败
[解决办法]
public int UpdateDishe(string dishUnitID, string dishNO, string dishNameCH, string dishNameEN, string py, string price, string cookingTime, string eatingTime, string inMenu, string UserID)
{
MySqlConnection conn = DBManager.GetConn();
try
{
string sql = "update dishes,dishunit set dishes.dishNO=?dishNO,dishes.nameCH=?dishNameCH, dishes.nameEN=?dishNameEN, dishes.py=?py ,dishunit.price=?price, dishunit.cookingTime=?cookingTime, dishunit.eatingTime=?eatingTime, dishunit.inMenu=?inMenu,dishunit.userID=?UserID,dishes.userID=?UserID,dishes.timestamp=now(),dishunit.timestamp=now() where dishes.dishID=dishunit.dishID and dishunit.dishUnitID=?dishUnitID";
MySqlCommand comm=new MySqlCommand (sql, conn);
comm.Parameters.Add(new MySqlParameter("dishNO", dishNO));
comm.Parameters.Add(new MySqlParameter("dishNameCH", dishNameCH));
comm.Parameters.Add(new MySqlParameter("dishNameEN", dishNameEN));
comm.Parameters.Add(new MySqlParameter("py", py.ToUpper()));
comm.Parameters.Add(new MySqlParameter("price", price));
comm.Parameters.Add(new MySqlParameter("cookingTime", cookingTime));
comm.Parameters.Add(new MySqlParameter("eatingTime", eatingTime));
comm.Parameters.Add(new MySqlParameter("inMenu", inMenu));
comm.Parameters.Add(new MySqlParameter("UserID", UserID));
comm.Parameters.Add(new MySqlParameter("dishUnitID", dishUnitID));
return comm.ExecuteNonQuery();
}
catch (Exception)
{
return -1;
throw;
}
finally
{
conn.Close();
}
}
