Question

标准表达式中数据类型不匹配。int insert = Convert.ToInt32(mycmd.ExecuteNonQuery()); 报错 哪位大虾帮

string settings = ConfigurationManager.AppSettings["SQLConnString"].ToString() + Server.MapPath(ConfigurationManager.AppSettings["dbPath"]) + ";";

OleDbConnection myconn = new OleDbConnection(settings);

myconn.Open();

string strsql = "insert into news(newstitle,newsneirong,addtime,username) value (" + this.TextBoxnewstitle.Text.ToString() + "," + this.TextBoxnewsneirong.Text.ToString() + ",getdate()," + username + ")";

OleDbCommand mycmd = new OleDbCommand(strsql, myconn);

int insert = Convert.ToInt32(mycmd.ExecuteNonQuery());

string settings = ConfigurationManager.AppSettings["SQLConnString"].ToString() + Server.MapPath(ConfigurationManager.AppSettings["userPath"]) + ";";

OleDbConnection myconn = new OleDbConnection(settings);

myconn.Open();

OleDbParameter username = new OleDbParameter(this.TextBoxusername.Text.ToString(), OleDbType.VarWChar, 100);
OleDbParameter userpassword = new OleDbParameter(this.TextBoxusername.Text.ToString(), OleDbType.VarWChar, 100);

string sqlstr = "select count(*) from [user] where username=" + username + " and userpassword=" + userpassword + "";

OleDbCommand mycmd = new OleDbCommand(sqlstr, myconn);//创建数据库命令

int count = Convert.ToInt32(mycmd.ExecuteScalar().ToString ());

Answer 1

mycmd.ExecuteNonQuery()的返回值就是INT型，把 Convert.ToInt32去掉

Answer 2

把“int insert = Convert.ToInt32(mycmd.ExecuteNonQuery());“替换为"try{int insert = Convert.ToInt32(mycmd.ExecuteNonQuery());}catch{int insert=0;}"
下面的count同理。。。。

Answer 3

ExecuteNonQuery 方法本身就返回int 类型 你为什么还要转换类型呢？

追问

int count = Convert.ToInt32(mycmd.ExecuteScalar().ToString ()); 这个也说不匹配 怎么能啊
这个是输入账号跟密码登录时提示的错误 判断是否在数据库中有数据

追答

你把后面的toString 去掉

追问

去了 tostring 还是不行啊

追答

吧错误发上来 在把相关代码发上来

追问

标准表达式中数据类型不匹配。

异常详细信息: System.Data.OleDb.OleDbException: 标准表达式中数据类型不匹配。

源错误: OleDbCommand mycmd = new OleDbCommand(sqlstr, myconn);//
int count = Convert.ToInt32(mycmd.ExecuteScalar()); 这句有错误
if (count >0 )

追答

public static bool isExt(string name,string pwd, string flag)
{
StringBuilder str = new StringBuilder();
str.Append("select count(*) from ht_user where user_name=@user_name and user_pwd=@user_pwd and user_flag=@user_flag");
SqlParameter[] p = {
new SqlParameter("@user_name",SqlDbType.VarChar,200,"user_name"),
new SqlParameter("@user_pwd",SqlDbType.VarChar,200,"user_pwd"),
new SqlParameter("@user_flag",SqlDbType.VarChar,200,"user_flag")
};
p[0].Value = name;
p[1].Value = MD5.MD5jm(pwd);
p[2].Value = flag;
return DbHelperSql1.Exists(str.ToString(), p);
}
SqlParameter 应该这么用