MSSQL - 存储过程Return返回值

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:		HF_Ultrastrong
-- Create date: 2015年7月19日22:09:24
-- Description:	判断是否有数据,并使用Return返回值
-- =============================================
CREATE PROCEDURE ReturnValue
AS
BEGIN
	if exists(select * from Tb_Category)
  return 100
else
  return -100
END

/// <summary>
/// 点击显示参数
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void Button1_Click(object sender, EventArgs e)
{
    SqlConnection con = new SqlConnection(ConfigurationManager.AppSettings["ConnectionString"].ToString());
    SqlCommand cmd = new SqlCommand("ReturnValue", con);
    cmd.CommandType = CommandType.StoredProcedure;

    //声明参数接收存储过程返回值
    SqlParameter returnValue = cmd.Parameters.Add("returnValue", SqlDbType.Int, 4);
    returnValue.Direction = ParameterDirection.ReturnValue;

    con.Open();
    cmd.ExecuteNonQuery();
    con.Close();

    this.Label1.Text = Convert.ToString(returnValue.Value);
}

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
-- =============================================
-- Author:		HF_Ultrastrong
-- Create date: 2015年7月19日22:09:24
-- Description:	判断是否有数据,并使用Return返回值
-- =============================================
CREATE PROCEDURE ReturnValue
	@10 int,
	@20 int,
	@30 int	
AS
BEGIN
	if exists(select * from Tb_Category)
  return 100
else
  return -100
END

/// <summary>
/// 点击显示参数
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void Button1_Click(object sender, EventArgs e)
{
    SqlConnection con = new SqlConnection(ConfigurationManager.AppSettings["ConnectionString"].ToString());
    SqlCommand cmd = new SqlCommand("ReturnValue", con);
    cmd.CommandType = CommandType.StoredProcedure;

    //参数数组
    SqlParameter[] para = new SqlParameter[]
    {
        new SqlParameter("@10", 10),
        new SqlParameter("@20", 20),
        new SqlParameter("@30", 30),
        new SqlParameter("@Return", SqlDbType.Int)
    };
    cmd.Parameters.AddRange(para);
    para[para.Length - 1].Direction = ParameterDirection.ReturnValue;

    con.Open();
    cmd.ExecuteNonQuery();
    con.Close();

    object obj = para[para.Length - 1].Value;
    this.Label1.Text = Convert.ToString(obj);
}