SQL字符串查询参数C＃

Question

我有这个代码... C＃中带参数的查询

var sql = @"select * from Passenger t0       
            join Ticket t1 on t0.PassengerID = t1.PassengerID               
            where t1.IsArrived = @IsArrived ";
            List<SqlParameter> parameters = new List<SqlParameter>() {  
                    new SqlParameter
                    {
                        ParameterName = "DateFrom",
                        Value = (object)fromDate ?? DBNull.Value,
                        DbType = System.Data.DbType.DateTime
                    },
                    new SqlParameter
                    {
                        ParameterName = "DateTo",
                        Value = (object)toDate ?? DBNull.Value,
                        DbType = System.Data.DbType.DateTime
                    },
                    new SqlParameter
                    {
                        ParameterName = "IsArrived",
                        Value = route,
                        DbType =System.Data.DbType.Boolean
                    },
                        new SqlParameter
                    {
                        ParameterName = "Search",
                        Value = $"'%{searchString}%'",
                        DbType = System.Data.DbType.String
                    }
                };
            var sqlQuery = sql +
                (fromDate != null ? "and t1.DateFrom >= @DateFrom " : " ") +
                (toDate != null ? "and @DateTo >= t1.DateFrom" : " ") +
                (!String.IsNullOrEmpty(searchString) ? "and (t0.FirstName like @Search or t0.LastName like @Search)" : " ");

参数＆＃34; @ Search＆＃34;坏了 - 如何修改此查询才能工作？ 我不知道如何为此参数编写值。 我试过了

 Value = $@"'%{searchString}%'"
 Value = @"'%"+searchString+"%'",
 Value = $"\u0027\u0025{searchString}\u0025\u0027",
 Value = "\u0027\u0025"+searchString+"\u0025\u0027",
 Value = "\'%"+searchString+"%\'"

Answer 1

var sqlQuery = sql + (fromDate != null ? "and t1.DateFrom >= @DateFrom " : " ") + (toDate != null ? "and @DateTo >= t1.DateFrom" : " ") + (!String.IsNullOrEmpty(searchString) ? "and (t0.FirstName like @Search or t0.LastName like ' + @Search+ ')" : " ");

不要将@Search保留在字符串中。