asp.net 存储过程 input/output 参数

Question

我正在尝试将单个输入参数传递给存储过程，我认为该存储过程声明了 OUTPUT 参数，但似乎是 input/output 变量，因此给我一条错误消息，指出其中一个没有为参数提供值。

C#调用代码设置如下：

protected void CheckBoxClassRegion_btnSubmit(object sender, EventArgs e)
{
    date    @date;             /* Variable for the date of the game     */
    varchar @HomeTeam;         /* The name of the high school team      */
    varchar @AwayTeam;         /* The name of the other H.s. team       */
    int     @TeamID;           /* The ID number of the high school team */
    AddressText.Text = "";
    /**********************************************************************/
    /* The code below will initialize the connection to the database.     */
    /* As the connection string to the SQL database is defined as conn,   */
    /* the open method from conn will connect to the database, and the    */
    /* cmd variable will call on the stored procedure GetSchedule.        */
    /**********************************************************************/
    string strcon   = WebConfigurationManager.ConnectionStrings["FollowingHSFootballConnectionString"].ConnectionString;
    SqlConnection conn = new SqlConnection(strcon);
    conn.Open();
    SqlCommand cmd  = new SqlCommand("GetSchedule", conn);
    cmd.CommandType = CommandType.StoredProcedure;

    /**********************************************************************/
    /* The for loop below will determine which items from the checkbox    */
    /* were selected from the input and use the High School team name to  */
    /* pass to the stored procedure 'GetSchedule' to return the dates,    */
    /* home team and away team each game.                                 */
    /**********************************************************************/
                                                                            /**********************************************************************/
    foreach (ListItem item in CheckBoxClassRegion.Items)                    /* This loop will go through all of the checkboxed items              */
    {                                                                       /**********************************************************************/
        if (item.Selected == true)                                          /*    If this team has been selected                                  */
        {                                                                   /**********************************************************************/
            cmd.Parameters.AddWithValue("@TeamName", item.Text);            /*       Pass input parameter "Team Name"                             */
            SqlDataReader reader = cmd.ExecuteReader();                     /*       Utilize the reader function to ensure all games are included */ 
            while (reader.Read())                                           /*       While there are still items to be read                       */
            {                                                               /**********************************************************************/
                cmd.Parameters.Add("@date", SqlDbType.Date);
                cmd.Parameters["@date"].Direction = ParameterDirection.Output;

                cmd.Parameters.Add("@HomeTeam", SqlDbType.VarChar, 25);
                cmd.Parameters["@HomeTeam"].Direction = ParameterDirection.Output;

                cmd.Parameters.Add("@AwayTeam", SqlDbType.VarChar, 25);
                cmd.Parameters["@AwayTeam"].Direction = ParameterDirection.Output;

                cmd.ExecuteNonQuery();                                          /*       Execute the stored procedure                                 */

                Console.WriteLine(cmd.Parameters["@GameDate"].Value);
                Console.WriteLine(cmd.Parameters["@HomeTeam"].Value);
                Console.WriteLine(cmd.Parameters["@AwayTeam"].Value);
                Console.ReadLine(); 
            }

存储过程：

ALTER PROCEDURE [dbo].[GetSchedule]

    @teamname varchar(25),
    @date Date OUTPUT,
    @HomeTeam varchar(25) OUTPUT,
    @AwayTeam varchar(25) OUTPUT

AS
BEGIN

    SET NOCOUNT ON;


    SELECT HomeSchedule.Date, HomeTeam.HighSchoolName, AwayTeam.HighSchoolName
    from (
      (Schedule$ as HomeSchedule inner join HighSchoolFootballTeam$ as HomeTeam 
        on HomeSchedule.HomeTeamID = HomeTeam.HighSchoolTeamID)
     inner join 
      (Schedule$ as AwaySchedule inner join HighSchoolFootballTeam$ as AwayTeam
        on AwaySchedule.AwayTeamID = AwayTeam.HighSchoolTeamID) 
     on HomeSchedule.GameID = AwaySchedule.GameID)
     where HomeTeam.HighSchoolName = @teamname or AwayTeam.HighSchoolName = @teamname
    Order by HomeSchedule.Date

END

如何让 @Date、@HomeTeam 和 @AwayTeam 的输出变量只作为输出而不是 input/output 变量，这样存储过程就不会期待他们的输入值？

Answer 1

您的存储过程具有设置为输入参数的 @teamname 参数，但您未在 C# 代码中为 @teamname 参数设置任何值，因此这就是您收到错误的原因。您需要为 @teamname 参数设置一个值，如下所示。

while (reader.Read())                                           /*       While there are still items to be read                       */
{                                                               /**********************************************************************/
    cmd.Parameters.Add("@teamname", SqlDbType.VarChar, 25);
    cmd.Parameters["@teamname"].Value = ...; // set the value here

    cmd.Parameters.Add("@date", SqlDbType.Date);
    cmd.Parameters["@date"].Direction = ParameterDirection.Output;

    cmd.Parameters.Add("@HomeTeam", SqlDbType.VarChar, 25);
    cmd.Parameters["@HomeTeam"].Direction = ParameterDirection.Output;

    cmd.Parameters.Add("@AwayTeam", SqlDbType.VarChar, 25);
    cmd.Parameters["@AwayTeam"].Direction = ParameterDirection.Output;

    cmd.ExecuteNonQuery();                                          /*       Execute the stored procedure                                 */

    Console.WriteLine(cmd.Parameters["@GameDate"].Value);
    Console.WriteLine(cmd.Parameters["@HomeTeam"].Value);
    Console.WriteLine(cmd.Parameters["@AwayTeam"].Value);
    Console.ReadLine(); 
}

编辑

查看更完整的代码后，这是你的错误

cmd.Parameters.AddWithValue("@TeamName", item.Text);
SqlDataReader reader = cmd.ExecuteReader();

您在执行 SqlDataReader reader = cmd.ExecuteReader(); 时没有添加 @date、@HomeTeam 和 @AwayTeam 参数，这就是您收到错误的原因。您应该在执行 cmd.ExecuteReader() 之前添加这三个参数。您还需要使用 command.Parameters.Clear(); 清除 cmd 的参数，因为您在循环内使用 cmd 并删除 cmd.ExecuteNonQuery() 因为调用时您已经在执行存储过程cmd.ExecuteReader()。更改您的代码如下

if (item.Selected == true) { cmd.Parameters.Clear(); cmd.Parameters.AddWithValue("@TeamName", item.Text); cmd.Parameters.Add("@date", SqlDbType.Date); cmd.Parameters["@date"].Direction = ParameterDirection.Output; cmd.Parameters.Add("@HomeTeam", SqlDbType.VarChar, 25); cmd.Parameters["@HomeTeam"].Direction = ParameterDirection.Output; cmd.Parameters.Add("@AwayTeam", SqlDbType.VarChar, 25); cmd.Parameters["@AwayTeam"].Direction = ParameterDirection.Output; SqlDataReader reader = cmd.ExecuteReader(); while (reader.Read()) { Console.WriteLine(cmd.Parameters["@GameDate"].Value); Console.WriteLine(cmd.Parameters["@HomeTeam"].Value); Console.WriteLine(cmd.Parameters["@AwayTeam"].Value); Console.ReadLine(); }

asp.net 存储过程 input/output 参数

asp.net stored procedure input/output parameter

c#

sql-server

asp.net

stored-procedures