mysql 查询语句 参数 mysql参数化查询语句有关问题

mysql参数化查询语句问题

部分代码如下：

using(MySqlConnectionconn=newMySqlConnection(connectionString))

{

conn.Open();

MySqlCommandcmd=newMySqlCommand();

cmd.Connection=conn;

MySqlTransactionts=conn.BeginTransaction();

try

{

for(inti=0;i

{

cmd.Parameters.AddWithValue("？PrimaryID",dt.Rows[i][1]);

mandText="select*frominfomine_bulletinwherePrimaryID=？PrimaryID";

objectob=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

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------解决方案--------------------

publicintUpdateDishe(stringdishUnitID,stringdishNO,stringdishNameCH,stringdishNameEN,stringpy,stringprice,stringcookingTime,stringeatingTime,stringinMenu,stringUserID)

{

MySqlConnectionconn=DBManager.GetConn();

try

{

stringsql="updatedishes,dishunitsetdishes.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()wheredishes.dishID=dishunit.dishIDanddishunit.dishUnitID=?dishUnitID";

MySqlCommandcomm=newMySqlCommand(sql,conn);

comm.Parameters.Add(newMySqlParameter("dishNO",dishNO));

comm.Parameters.Add(newMySqlParameter("dishNameCH",dishNameCH));

comm.Parameters.Add(newMySqlParameter("dishNameEN",dishNameEN));

comm.Parameters.Add(newMySqlParameter("py",py.ToUpper()));

comm.Parameters.Add(newMySqlParameter("price",price));

comm.Parameters.Add(newMySqlParameter("cookingTime",cookingTime));

comm.Parameters.Add(newMySqlParameter("eatingTime",eatingTime));

comm.Parameters.Add(newMySqlParameter("inMenu",inMenu));

comm.Parameters.Add(newMySqlParameter("UserID",UserID));