Question

我希望我的存储过程从表中选择数据并将此数据放入文本框中。基本上，这是当一个人从下拉菜单中选择一个项目然后想要编辑该项目时使用的。

我在这里做错了什么？

C＃

    string eventName = TextBoxEventName.Text;
    string location = TextBoxLocation.Text;
    string city = TextBoxCity.Text;
    string state = DropDownListState2.SelectedValue;
    string description = TextBoxDescription.Text;

    string eventSelected = DropDownListEvents.SelectedValue; 

    using (SqlConnection sqlConn = new SqlConnection(ConfigurationManager.ConnectionStrings["Events2"].ConnectionString))
    { using (var command = sqlConn.CreateCommand())
        {

            command.CommandType = System.Data.CommandType.StoredProcedure;
            command.CommandText = "spGetEvent";

             command.Parameters.Add("@EventId", SqlDbType.Int).Value = eventSelected;

             using (var reader = command.ExecuteReader())
             {
                 while (reader.Read())
                 {

                     command.Parameters.Add("@EventName", SqlDbType.NVarChar, 255).Value = eventName;
                     command.Parameters.Add("@Location", SqlDbType.NVarChar, 255).Value = location;
                     command.Parameters.Add("@City", SqlDbType.NVarChar, 30).Value = city;
                     command.Parameters.Add("@State", SqlDbType.NVarChar, 2).Value = state;
                     command.Parameters.Add("@Description", SqlDbType.NVarChar, -1).Value = description;
                 }
             }

我的存储过程的一部分

PROCEDURE [dbo].[spGetEvent]
        @EventId int,
        @EventName nvarchar(255),
        @Location nvarchar(255),
        @City nvarchar(30),
        @State nvarchar(2),
        @Description nvarchar(max)
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    -- Insert statements for procedure here
    SELECT *
    FROM Event
    WHERE EventId = @EventId AND 
    EventName  = @EventName AND 
    Location = @Location AND 
    City = @City AND 
    State = @State AND 
    Description = @Description
END

Answer 1

在设置所有参数之前，您正在执行Command。

using (SqlConnection sqlConn = new SqlConnection(ConfigurationManager.ConnectionStrings["Events2"].ConnectionString))
{ using (var command = sqlConn.CreateCommand())
    {

        command.CommandType = System.Data.CommandType.StoredProcedure;
        command.CommandText = "spGetEvent";

         command.Parameters.Add("@EventId", SqlDbType.Int).Value = eventSelected;

        using (var reader = command.ExecuteReader())
         {
             if(reader.Read())
             {
                 eventName.Text = reader["EventName"].ToString();
                 location.Text = reader["Location"].ToString();
                 city.Text = reader["City"].ToString();
                 state.Text = reader["State"].ToString();
                 description.Text = reader["Description"].ToString();
             }
         }
    }
}

将存储过程更改为仅接受EventId作为参数：

PROCEDURE [dbo].[spGetEvent]
        @EventId int
AS
BEGIN
    -- SET NOCOUNT ON added to prevent extra result sets from
    -- interfering with SELECT statements.
    SET NOCOUNT ON;

    -- Insert statements for procedure here
    SELECT *
    FROM Event
    WHERE EventId = @EventId 
END

存储过程 - 使用参数选择并填充文本框

1 个答案: