列类型XML不返回XML

I have an XML stored in the database table that I am trying to retrieve (variable strXML) below. Any reason why this is coming as blank? Please help. When I execute the procedure directly in database, it's working fine.

我有一个XML存储在我试图检索的数据库表中（变量strXML）。有什么理由说这是空白的？请帮忙。当我直接在数据库中执行该过程时，它工作正常。

        try
        {
            // Open the database connection
            using (SqlConnection myConn = my.openConnection("~",PConnectionString"))
            {
                // Initialize the SQL command object.
                using (SqlCommand myCOmmand = new SqlCommand("getCycleXML", myConn))
                {
                    myCOmmand.CommandType = CommandType.StoredProcedure;
                    // Add the parameters

                    SqlParameter parameter2 = new SqlParameter("@emailID", SqlDbType.NVarChar, 128);
                    parameter2.Value = strEmailID;
                    parameter2.Direction = ParameterDirection.Input;
                    myCOmmand.Parameters.Add(parameter2);

                    SqlParameter parameter1 = new SqlParameter("@pCode", SqlDbType.VarChar, 50);
                    parameter1.Value = strPCode;
                    parameter1.Direction = ParameterDirection.Input;
                    myCOmmand.Parameters.Add(parameter1);

                    SqlParameter parameter7 = new SqlParameter("@cID", SqlDbType.Int);
                    parameter7.Direction = ParameterDirection.Input;
                    parameter7.Value = icID;
                    myCOmmand.Parameters.Add(parameter7);

                    SqlParameter parameter9 = new SqlParameter("@cycleXML", SqlDbType.Xml);
                    parameter9.Direction = ParameterDirection.Output;
                    myCOmmand.Parameters.Add(parameter9);


                    SqlParameter parameter10 = new SqlParameter("@msg", SqlDbType.VarChar, 50);
                    parameter10.Direction = ParameterDirection.Output;
                    myCOmmand.Parameters.Add(parameter10);

                    SqlParameter parameter11 = new SqlParameter("@Success", SqlDbType.Int);
                    parameter11.Direction = ParameterDirection.Output;
                    myCOmmand.Parameters.Add(parameter11);
                    //Execute the command

                    myCOmmand.ExecuteNonQuery();
                    // Read the values of the output parameters
                    strXML = myCOmmand.Parameters["@cycleXML"].Value.ToString();

                   =================================================

Stored procedure definition is as follows:

存储过程定义如下：

  USE [DMac]
  GO

  SET ANSI_NULLS ON
  GO
  SET QUOTED_IDENTIFIER ON
  GO

  CREATE PROCEDURE [dbo].[getCycleXML]
  @emailID Nvarchar(128),
  @cID varchar(50),
  @pCode varchar(50),
  @cycleXML xml output,
  @Success int output, 
  @msg varchar(50) output  

  AS
  BEGIN
  select XMLDefectCycle from dbo.CycleXML where EmailID=@emailID and PCode=@pCode and CID=@cID 
  END

==============================

Why the code is coming back as a blank XML. I checked that for the given parameters in the database I was expecting an XML from the database.

为什么代码将作为空白XML返回。我检查了数据库中的给定参数，我期待数据库中的XML。

1 个解决方案

#1

You're not setting the output parameter in your stored procedure

您没有在存储过程中设置输出参数

It should be

它应该是

select @cycleXML = XMLDefectCycle 
from dbo.CycleXML where EmailID=@emailID and PCode=@pCode and CID=@cID

or call your stored procedure with ExecuteScalar() instead

或者使用ExecuteScalar（）调用存储过程

#1