Insert into C# with SQLCommand

Question

What's the best way to INSERT data into a database?

This is what I have but it's wrong..

cmd.CommandText = "INSERT INTO klant(klant_id,naam,voornaam) VALUES(@param1,@param2,@param3)";

cmd.Parameters.Add(new SqlParameter("@param1", klantId));
cmd.Parameters.Add(new SqlParameter("@param2", klantNaam));
cmd.Parameters.Add(new SqlParameter("@param3", klantVoornaam));

The function add data into the listBox

http://www.pictourl.com/viewer/37e4edcf (link is dead)

but not into the database..

http://www.pictourl.com/viewer/4d5721fc (link is dead)

The full function:

private void Form1_Load(object sender, EventArgs e)
{            
    conn2 = new SqlConnection();
    conn2.ConnectionString = ConfigurationManager.ConnectionStrings["connSpionshopString"].ConnectionString;
}

private void button2_Click(object sender, EventArgs e)
{         
    string sqlCmd = "SELECT naam,voornaam,klant_id FROM klant;";
    SqlCommand cmd = new SqlCommand(sqlCmd, conn2);

    conn2.Open();

    using(SqlDataReader reader = cmd.ExecuteReader())
    {
        while (reader.Read())
        {
            listBox2.Items.Add(reader.GetString(0) + " " + reader.GetString(1) + "  (" + reader.GetInt16(2) + ")");
        }  
    }
    conn2.Close();
}

private void button4_Click(object sender, EventArgs e)
{
    int klantId = Convert.ToInt32(textBox1.Text);
    string klantNaam = textBox2.Text;
    string klantVoornaam = textBox3.Text;

    conn2.Open();

    SqlCommand cmd = new SqlCommand();
    cmd.Connection = conn2;
    cmd.CommandText = "INSERT INTO klant(klant_id, naam, voornaam)   VALUES(@param1,@param2,@param3)";

    cmd.Parameters.AddWithValue("@param1", klantId);
    cmd.Parameters.AddWithValue("@param2", klantNaam);
    cmd.Parameters.AddWithValue("@param3", klantVoornaam);

    cmd.ExecuteNonQuery(); 

    conn2.Close();
}

Answer 1

Try confirm the data type (SqlDbType) for each parameter in the database and do it this way;

 using(SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["connSpionshopString"].ConnectionString))
 {
            connection.Open();
            string sql =  "INSERT INTO klant(klant_id,naam,voornaam) VALUES(@param1,@param2,@param3)";
            using(SqlCommand cmd = new SqlCommand(sql,connection)) 
            {
                  cmd.Parameters.Add("@param1", SqlDbType.Int).Value = klantId;  
                  cmd.Parameters.Add("@param2", SqlDbType.VarChar, 50).Value = klantNaam;
                  cmd.Parameters.Add("@param3", SqlDbType.VarChar, 50).Value = klantVoornaam;
                  cmd.CommandType = CommandType.Text;
                  cmd.ExecuteNonQuery(); 
            }
 }

Answer 2

you can use implicit casting AddWithValue

cmd.Parameters.AddWithValue("@param1", klantId);
cmd.Parameters.AddWithValue("@param2", klantNaam);
cmd.Parameters.AddWithValue("@param3", klantVoornaam);

sample code,

using (SqlConnection conn = new SqlConnection("connectionString")) 
{
    using (SqlCommand cmd = new SqlCommand()) 
    { 
        cmd.Connection = conn;
        cmd.CommandType = CommandType.Text;
        cmd.CommandText = @"INSERT INTO klant(klant_id,naam,voornaam) 
                            VALUES(@param1,@param2,@param3)";  

        cmd.Parameters.AddWithValue("@param1", klantId);  
        cmd.Parameters.AddWithValue("@param2", klantNaam);  
        cmd.Parameters.AddWithValue("@param3", klantVoornaam);  

        try
        {
            conn.Open();
            cmd.ExecuteNonQuery(); 
        }
        catch(SqlException e)
        {
            MessgeBox.Show(e.Message.ToString(), "Error Message");
        }

    } 
}

Answer 3

using (SqlConnection connection = new SqlConnection(connectionString)) 
{
    connection.Open(); 
    using (SqlCommand command = connection.CreateCommand()) 
    { 
        command.CommandText = "INSERT INTO klant(klant_id,naam,voornaam) VALUES(@param1,@param2,@param3)";  

        command.Parameters.AddWithValue("@param1", klantId));  
        command.Parameters.AddWithValue("@param2", klantNaam));  
        command.Parameters.AddWithValue("@param3", klantVoornaam));  

        command.ExecuteNonQuery(); 
    } 
}

Answer 4

You should avoid hardcoding SQL statements in your application. If you don't use ADO nor EntityFramework, I would suggest you to ad a stored procedure to the database and call it from your c# application. A sample code can be found here: How to execute a stored procedure within C# program and here http://msdn.microsoft.com/en-us/library/ms171921%28v=vs.80%29.aspx.

Answer 5

public class customer
{
    public void InsertCustomer(string name,int age,string address)
    {
        // create and open a connection object
        using(SqlConnection Con=DbConnection.GetDbConnection())
        {
            // 1. create a command object identifying the stored procedure
            SqlCommand cmd = new SqlCommand("spInsertCustomerData",Con);

            // 2. set the command object so it knows to execute a stored procedure
            cmd.CommandType = CommandType.StoredProcedure;

            SqlParameter paramName = new SqlParameter();
            paramName.ParameterName = "@nvcname";
            paramName.Value = name;
            cmd.Parameters.Add(paramName);

            SqlParameter paramAge = new SqlParameter();
            paramAge.ParameterName = "@inage";
            paramAge.Value = age;
            cmd.Parameters.Add(paramAge);

            SqlParameter paramAddress = new SqlParameter();
            paramAddress.ParameterName = "@nvcaddress";
            paramAddress.Value = address;
            cmd.Parameters.Add(paramAddress);

            cmd.ExecuteNonQuery();
        }
    }
}

Answer 6

You can use dapper library:

conn2.Execute(@"INSERT INTO klant(klant_id,naam,voornaam) VALUES (@p1,@p2,@p3)", 
                new { p1 = klantId, p2 = klantNaam, p3 = klantVoornaam });

BTW Dapper is a Stack Overflow project :)

UPDATE: I believe you can't do it simpler without something like EF. Also try to use using statements when you are working with database connections. This will close connection automatically, even in case of exception. And connection will be returned to connections pool.

private readonly string _spionshopConnectionString;

private void Form1_Load(object sender, EventArgs e)
{            
    _spionshopConnectionString = ConfigurationManager
          .ConnectionStrings["connSpionshopString"].ConnectionString;
}

private void button4_Click(object sender, EventArgs e)
{
    using(var connection = new SqlConnection(_spionshopConnectionString))
    {
         connection.Execute(@"INSERT INTO klant(klant_id,naam,voornaam) 
                              VALUES (@klantId,@klantNaam,@klantVoornaam)",
                              new { 
                                      klantId = Convert.ToInt32(textBox1.Text), 
                                      klantNaam = textBox2.Text, 
                                      klantVoornaam = textBox3.Text 
                                  });
    }
}

Answer 7

Use AddWithValue(), but be aware of the possibility of the wrong implicit type conversion.
like this:

cmd.Parameters.AddWithValue("@param1", klantId);
    cmd.Parameters.AddWithValue("@param2", klantNaam);
    cmd.Parameters.AddWithValue("@param3", klantVoornaam);