public void AddSqlParameters() 
{
// ...
// create categoriesDataSet and categoriesAdapter
// ...

  categoriesAdapter.SelectCommand.Parameters.Add(
    "@CategoryName", SqlDbType.VarChar, 80).Value = "toasters";
  categoriesAdapter.SelectCommand.Parameters.Add(
    "@SerialNum", SqlDbType.Int).Value = 239;
  categoriesAdapter.Fill(categoriesDataSet);
}

//引入命名空间
using System;
using System.Data;
using System.Data.SqlClient;

class MainClass
{
  static void Main(string[] args)
  {
    SqlConnection cn = new SqlConnection("Data Source=(local); Initial  Catalog = MyDatabase; User ID=sa;Password=");
    SqlCommand cmd = new SqlCommand("MyStoredProcedure", cn);
    cmd.CommandType = CommandType.StoredProcedure;
    SqlParameter param = new SqlParameter("@ReturnValue", SqlDbType.Int);
    cmd.Parameters.Add(param);
    cmd.Parameters.Add("MyFirstParameter", SqlDbType.Int);
    cmd.Parameters.Add("MySecondParameter", SqlDbType.Int).Direction =
    ParameterDirection.Output;
    SqlDataAdapter da = new SqlDataAdapter(cmd);
    
  }
}