Подскажите, как поправить в код! что бы пропала ошибка?

Question

 public string GetConfigParamByName(string paramName)
        {
            string res = "";
            con.Open();
            com = new OleDbCommand("Select Value from Configurations where ParamName = '" + paramName + "'", con);
            reader = com.ExecuteReader();
            if (reader)
            {
                res = reader.GetString(0);
            }
            con.Close();
            return res;
        }

Ошибка: Ошибка1 Неявное преобразование типа "System.Data.OleDb.OleDbDataReader" в "bool" невозможно

Как  ёё испарвить??

Answer 1

When you're going to stop this bad practice?

public string GetConfigParamByName(string paramName)
        {
            string res = "";
            con.Open();
            string sql = "Select Value from Configurations where ParamName = ?"; 
            com = new OleDbCommand(sql, con);
            com.Parameters.Add("@paramName", OleDbType.Char, 30).Value = paramName; 
            reader = com.ExecuteReader();
            while (reader.Read()) // the error was here
            {
                res = reader.GetString(0);
            }
            con.Close();
            return res;
        }

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For every expert, there is an equal and opposite expert. - Becker's Law


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Answer 2

When you're going to stop this bad practice?

public string GetConfigParamByName(string paramName)
        {
            string res = "";
            con.Open();
            string sql = "Select Value from Configurations where ParamName = ?"; 
            com = new OleDbCommand(sql, con);
            com.Parameters.Add("@paramName", OleDbType.Char, 30).Value = paramName; 
            reader = com.ExecuteReader();
            while (reader.Read()) // the error was here
            {
                res = reader.GetString(0);
            }
            con.Close();
            return res;
        }

---

For every expert, there is an equal and opposite expert. - Becker's Law


My blog

Что имеешь виду когда говоришь, Когда собирающийся останавливать эту плохую практику?

Answer 3

I meant - stop embedding parameters into the SQL string using string concatenation. Start to always use parameters and if you see code when you're not doing it, take a moment and fix it.

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For every expert, there is an equal and opposite expert. - Becker's Law


My blog