Elie Elie - 7 months ago 35
SQL Question

Parameterized Query for MySQL with C#

I have the code below (I've included what I believe are all relevant sections):

private String readCommand = "SELECT LEVEL FROM USERS WHERE VAL_1 = ? AND VAL_@ = ?;";
public bool read(string id)
{
level = -1;
MySqlCommand m = new MySqlCommand(readCommand);
m.Parameters.Add(new MySqlParameter("", val1));
m.Parameters.Add(new MySqlParameter("", val2));
MySqlDataReader r = m.ExecuteReader();
if (r.HasRows)
level = Convert.ToInt32(r.GetValue(0).ToString());
r.Close();
return true;
}


When I run this, I get an IndexOutOfBoundsException on adding the first parameter. What have I done wrong?

Answer

Try this instead:

private String readCommand = "SELECT LEVEL FROM USERS WHERE VAL_1 = @param_val_1 AND VAL_2 = @param_val_2;";
public bool read(string id)
{
    level = -1;
    MySqlCommand m = new MySqlCommand(readCommand);
    m.Parameters.AddWithValue("@param_val_1", val1);
    m.Parameters.AddWithValue("@param_val_2", val2);
    level = Convert.ToInt32(m.ExecuteScalar());
    return true;
}
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