How to use MySql select with c#

Question

Can anyone tell whats wrong with my code? I have tried a million different things and I cant seem to make it work. I need to make a select in my mysql database and use the id from the table with the specified name I take from a combobox.

I took that name from the combobox and put it into a variable named "nomeres", now I need to do a select with it and take the id from that name from the database. Everything I try to do results in a mysql syntax error in line 1, but I've tried alot of things and its always the same. The database is fine, I tried the select directly from it myself, no tables or columns names are incorrect. This is the code im using:

MySql.Data.MySqlClient.MySqlConnection dbConn = new MySql.Data.MySqlClient.MySqlConnection("Persist Security Info=False;server=localhost;database=notas;uid=root;password=" + dbpwd);

MySqlCommand cmd = dbConn.CreateCommand();
cmd.CommandText = "SELECT id from residentes WHERE nome ='" + nomeres;

try
{
    dbConn.Open();                
} catch (Exception erro) {
    MessageBox.Show("Erro" + erro);
    this.Close();
}

MySqlDataReader reader = cmd.ExecuteReader();

while (reader.Read())
{
    idnumber = reader.ToString();
}

Answer 1

as others have already pointed you towards right direction, i would like to suggest you to use parameterised queries to avoid SQL injection attacks.

Your query is open to SQL injection attacks so please read here

Try This: using parameterised SQL queries

cmd.CommandText = "SELECT id from residentes WHERE nome = @nome";
cmd.Parameters.AddWithValue("@nome",nomeres);