如何从存储过程返回 XML? [英] How do I return XML from a Stored Procedure?

问题描述

我创建了一个返回 XML 的存储过程，我还想在我创建的方法中返回该 XML.

I created a Stored Procedure that returns XML and I would like to also return that XML in a method I created.

我有两个问题.首先，经过一番搜索，不建议使用.ExecuteScalar();，因为它会截断超过2033个字符的字符串.

I'm having two issues. First, after doing some searching, it is not advised to use .ExecuteScalar(); because it truncates strings over 2033 characters.

因此，我找到了一个名为 ExecuteXMlReader() 的函数，但在运行于 .NET 4.0 (C#) 的 Visual Web Developer 2010 Express 中，它抛出错误 System.Data.SqlClient.SqlCommand' 不包含 'ExecuteXMlReader' 的定义，并且无法找到接受类型为 'System.Data.SqlClient.SqlCommand' 的第一个参数的扩展方法 'ExecuteXMlReader'"

So, I found a function called ExecuteXMlReader(), but in Visual Web Developer 2010 Express that runs on .NET 4.0 (C#) it is throwing the error "System.Data.SqlClient.SqlCommand' does not contain a definition for 'ExecuteXMlReader' and no extension method 'ExecuteXMlReader' accepting a first argument of type 'System.Data.SqlClient.SqlCommand' could be found"

这是我的存储过程:

CREATE PROCEDURE dbo.GETReport
    (@ReportDate date)
AS
SELECT * FROM ReportTbl
WHERE ReportDate = @ReportDate
for xml auto, elements

set nocount on;

RETURN

这是我的方法:

using System.Data;
using System.Data.SqlClient;

...

        //connect        
        SqlConnection conn = new SqlConnection("Data Source=localhost; User Id=foo; Password=foo; Initial Catalog=Database1");
        conn.Open();

        //create command
        SqlCommand cmd = new SqlCommand("dbo.GETReport", conn);
        cmd.Parameters.AddWithValue("@ReportDate", "3/24/2011"); 
        cmd.CommandType = CommandType.StoredProcedure;

        DataReader rd = cmd.ExecuteXMlReader(); //this is where error is occuring
        //also, it is throwing an error for DataReader as well saying there is no
        //type of namespace with that name
        rd.Read();

        string s = rd.ReadOuterXml(); //also dont know if this is how i should return the XML

其次，除了ExecuteXMLReader()的问题，我不知道返回一个字符串是否是返回XML的正确方式......是否还有另一种对象类型我应该转换成??或者我应该使用的其他功能??

Second, in addition to the ExecuteXMLReader() issue, I don't know if returning a string is the proper way of returning XML in the first place... Is there another object type I should convert it to?? Or another function I should use??

提前谢谢你！！

推荐答案

首先，SqlCommand 有一个 ExecuteXmlReader 方法，而不是你的 ExecuteXMlReader写道(这是拼写错误).二、SqlCommand.ExecuteXmlReader方法返回 XmlReader 类型的值，而不是您的示例中的 DataReader 类型.因此，将您的代码更改为:

First, SqlCommand has a ExecuteXmlReader method, not ExecuteXMlReader as you wrote (this is misspelling). Second, SqlCommand.ExecuteXmlReader method returns a value of type XmlReader, not a DataReader as is in your example. So changing your code to:

using (XmlReader reader = cmd.ExecuteXmlReader())
{
    while(reader.Read())
    {
        string s = reader.ReadOuterXml();
        // do something with s
    }
}

应该可以解决问题.

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