Sql CMD Command with parameters

Question

I got this code from Stackoverflow to insert data in table. But I wonder what it actually doing can someone please explain me this, What cmd.Parameters.add method does? 2: Why data conversion required? 3: What is @BSal here ?

cmd.Parameters.Add("@BSal", SqlDbType.Decimal).Value = Convert.ToDecimal(txtBSal.Text);
                    cmd.Connection = Connection.con;
                    cmd.ExecuteNonQuery();

Answer 1

@BSal is the name of a SQL parameter in your stored procedure or SQL statement.

cmd.Parameters.Add fills in a SQL parameter's values. The convert to Decimal is required because the type of the parameter is SqlDbType.Decimal and currently txtBSal is a text box, so you must convert the string to a decimal before it can be used.