title: INSERT data from Textbox to Postgres SQL
body: <p>I just learn how to connect C# and PostgresSQL.
  I want to INSERT data from tb1(Textbox) and tb2 to database. But I don't know how to code
  My previous code is SELECT from database.
  this is my code</p>
  
  <pre><code>private void button1_Click(object sender, EventArgs e)
      {
          bool blnfound = false;
          NpgsqlConnection conn = new NpgsqlConnection("Server=127.0.0.1;Port=5432;User Id=postgres;Password=admin123;Database=Login");
          conn.Open();
          NpgsqlCommand cmd = new NpgsqlCommand("SELECT * FROM login WHERE name='" + tb1.Text + "' and password = '" + tb2.Text + "'",conn);
          NpgsqlDataReader dr = cmd.ExecuteReader();
  
          if (dr.Read())
          {
              blnfound = true;
              Form2 f5 = new Form2();
              f5.Show();
              this.Hide();
          }
  
          if (blnfound == false)
          {
              MessageBox.Show("Name or password is incorrect", "Message Box", MessageBoxButtons.OK, MessageBoxIcon.Exclamation, MessageBoxDefaultButton.Button1);
              dr.Close();
              conn.Close();
          }
      }
  </code></pre>
  
  <p>So please help me the code.</p>