以下是一个示例XML数据文件:
<?xml version="1.0" encoding="utf-8"?>
<AssignmentHistory Version="171804">
<W20160104>
<StudentItems>
<Item>
<Name Counsel="13" NextCounsel="0" Completed="1">Name 1</Name>
<Type>Bible Reading (Main)</Type>
</Item>
</StudentItems>
</W20160104>
<W20160111>
<StudentItems>
<Item>
<Name Counsel="9" NextCounsel="9" Completed="0">Name 2</Name>
<Type>Bible Reading (Main)</Type>
</Item>
<Item Description="Initial Call">
<Name Counsel="37" NextCounsel="38" Completed="1">Name 1</Name>
<Type>#1 Student (Main)</Type>
</Item>
<Item>
<Name>Name 3</Name>
<Type>Assistant</Type>
</Item>
<Item>
<Name Counsel="48" NextCounsel="49" Completed="1">Name 4</Name>
<Type>#2 Student (Main)</Type>
</Item>
<Item>
<Name>Name 5</Name>
<Type>Assistant</Type>
</Item>
<Item>
<Name Counsel="27" NextCounsel="30" Completed="1">Name 6</Name>
<Type>#3 Student (Main)</Type>
</Item>
<Item>
<Name>Name 7</Name>
<Type>Assistant</Type>
</Item>
</StudentItems>
</W20160111>
</AssignmentHistory>
我编写了一些代码来读取XML数据文件并找到给定名称的未来分配历史记录。例如,如果周是2016年1月4日,并且我们正在获取名称1的历史记录,那么我的代码将返回一个条目列表(在本例中,仅为1,2016年1月11日的一周)。
我的代码:
我的方法表现良好:
public void ExtractFutureStudentHistory(String strStudent, DateTime datWeekOfMeeting, String strHistoryDatabase, out DateTime[] aryFutureDates, out string[] aryFutureAssignTypes, out int[] aryFutureStudyNo)
{
XmlDocument docAssignHistory = new XmlDocument();
aryFutureDates = null;
aryFutureAssignTypes = null;
aryFutureStudyNo = null;
List<DateTime> listFutureDates = new List<DateTime>();
List<string> listFutureAssignTypes = new List<string>();
List<int> listFutureStudyNo = new List<int>();
try
{
docAssignHistory.Load(strHistoryDatabase);
// The data in the XML should already be in ascending date order
// The data we want:
// AssignmentHistory/<WYYYYMMDD>/StudentItems/Item/Name
// AssignmentHistory/<WYYYYMMDD>/StudentItems/Item/Type
XmlNodeList listHistory = docAssignHistory.SelectNodes("AssignmentHistory/*/StudentItems/Item[Name='" + strStudent + "']");
foreach(XmlNode nodeHistoryItem in listHistory)
{
XmlNode weekNode = nodeHistoryItem.ParentNode.ParentNode;
String strWeekDate = weekNode.Name.Substring(1); // This skips the preceding "W"
DateTime dateHistoryItemWeekOfMeeting = new DateTime(Convert.ToInt32(strWeekDate.Substring(0, 4)),
Convert.ToInt32(strWeekDate.Substring(4, 2)),
Convert.ToInt32(strWeekDate.Substring(6, 2)));
if (dateHistoryItemWeekOfMeeting.Date > datWeekOfMeeting.Date)
{
// We need to include it
listFutureDates.Add(dateHistoryItemWeekOfMeeting);
listFutureStudyNo.Add(Convert.ToInt32(nodeHistoryItem.SelectSingleNode("Name").Attributes["Counsel"].Value));
listFutureAssignTypes.Add(nodeHistoryItem.SelectSingleNode("Type").InnerText);
}
}
aryFutureDates = listFutureDates.ToArray();
aryFutureStudyNo = listFutureStudyNo.ToArray();
aryFutureAssignTypes = listFutureAssignTypes.ToArray();
}
catch (Exception ex)
{
SimpleLog.Log(ex);
}
}
可能逻辑可以简化,但它可以工作。我的问题是我的方法是C#.NET DLL的一部分。目前,我有这种公共接口方法:
[Guid("xx")]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
[ComVisible(true)]
public interface IMSAToolsLibraryInterface
{
void ExtractFutureStudentHistory(String strStudent, DateTime datWeekOfMeeting, String strHistoryDatabase, out DateTime[] aryFutureDates, out string[] aryFutureAssignTypes, out Int32[] aryFutureStudyNo);
}
工作正常。在C ++ MFC中,我有三个SAFEARRAY**
个对象,一个类型为BSTR
,一个类型为DATE
,另一个类型为int
。它本身没问题。
我的问题是,我的功能可以更改为输出单个对象列表吗?例如,如果我创建了一个类:
StudentItem
有三个成员变量用于日期,作业类型和研究编号。
我尝试将我的函数参数更改为out List<StudentItem>
,但这不起作用。然后我将其更改为out StudentItem[]
,我仍然无法使用它。
我将StudentItem
声明为具有三名成员的基本struct
。声明此对象的正确方法是什么,以便我可以将其作为数组传回给MFC使用?
感谢。
第1步:
我在DLL项目中添加了一个新对象:
[Guid("xx")]
[ComVisible(true)]
public struct StudentItem
{
public string Type { get; set; }
public DateTime Week { get; set; }
public int Study { get; set; }
}
第2步:
我在界面中添加了一个引用:
void ExtractFutureStudentHistory2(String strStudent, DateTime datWeekOfMeeting, String strHistoryDatabase, out StudentItem[] aryStudentItems);
第3步:
我添加了调整后的方法:
public void ExtractFutureStudentHistory2(String strStudent, DateTime datWeekOfMeeting, String strHistoryDatabase, out StudentItem[] aryStudentItems)
{
XmlDocument docAssignHistory = new XmlDocument();
aryStudentItems = null;
List<StudentItem> listStudentItems = new List<StudentItem>();
try
{
docAssignHistory.Load(strHistoryDatabase);
// The data in the XML should already be in ascending date order
// The data we want:
// AssignmentHistory/<WYYYYMMDD>/StudentItems/Item/Name
// AssignmentHistory/<WYYYYMMDD>/StudentItems/Item/Type
XmlNodeList listHistory = docAssignHistory.SelectNodes("AssignmentHistory/*/StudentItems/Item[Name='" + strStudent + "']");
foreach (XmlNode nodeHistoryItem in listHistory)
{
XmlNode weekNode = nodeHistoryItem.ParentNode.ParentNode;
String strWeekDate = weekNode.Name.Substring(1); // This skips the preceding "W"
DateTime dateHistoryItemWeekOfMeeting = new DateTime(Convert.ToInt32(strWeekDate.Substring(0, 4)),
Convert.ToInt32(strWeekDate.Substring(4, 2)),
Convert.ToInt32(strWeekDate.Substring(6, 2)));
if (dateHistoryItemWeekOfMeeting.Date > datWeekOfMeeting.Date)
{
StudentItem oItem = new StudentItem();
oItem.Week = dateHistoryItemWeekOfMeeting;
oItem.Type = nodeHistoryItem.SelectSingleNode("Type").InnerText;
oItem.Study = Convert.ToInt32(nodeHistoryItem.SelectSingleNode("Name").Attributes["Counsel"].Value);
listStudentItems.Add(oItem);
}
}
aryStudentItems = listStudentItems.ToArray();
}
catch (Exception ex)
{
SimpleLog.Log(ex);
}
}
第4步:
我编译DLL。我遇到了问题:
1&gt; C:\ Program Files(x86)\ Microsoft Visual 工作室\ 2017年\社区\的MSBuild \ 15.0 \斌\ Microsoft.Common.CurrentVersion.targets(4556,5): 警告:键入库导出器警告处理 'MSAToolsLibrary.StudentItem.k__BackingField,MSAToolsLibrary'。 警告:公共结构包含一个或多个非公共字段 将被出口。
答案 0 :(得分:1)
这里有两个选项:
删除自动实现的属性。这以一种众所周知的方式公开您的结构,COM客户端可以使用它:
[Guid("xx")]
[ComVisible(true)]
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct StudentItem
{
[MarshalAs(UnmanagedType.BStr)]
public string Type;
public DateTime Week;
public int Study;
}
...或使用界面。 COM接口完全支持属性:
[Guid("xx")]
[ComVisible(true)]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface StudentItem
{
string Type { get; set; }
DateTime Week { get; set; }
int Study { get; set; }
}
作为旁注,您可以考虑按如下方式更改方法:
StudentItem[] ExtractFutureStudentHistory2(String strStudent, DateTime datWeekOfMeeting, String strHistoryDatabase);
这使得在客户端中使用该方法变得更加容易,因为现在该数组被声明为标准返回参数。
答案 1 :(得分:-2)
您可以返回结构分配,如下面的代码所示。我使用xml linq将整个xml解析为一个列表。您可以查询列表对象
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml;
using System.Xml.Linq;
namespace ConsoleApplication73
{
class Program
{
const string FILENAME = @"c:\temp\test.xml";
static void Main(string[] args)
{
XDocument doc = XDocument.Load(FILENAME);
List<Assignment> assignments = doc.Root.Elements().Select(x => new
{
items = x.Descendants("Item").Select(y => new Assignment()
{
date = DateTime.ParseExact(x.Name.LocalName.Substring(1),"yyyyMMdd",System.Globalization.CultureInfo.InvariantCulture),
_type = (string)y.Descendants("Type").FirstOrDefault(),
name = (string)y.Descendants("Name").FirstOrDefault(),
counsel = (string)y.Descendants("Name").FirstOrDefault().Attribute("Counsel"),
nextCounsil = (string)y.Descendants("Name").FirstOrDefault().Attribute("NextCounsel"),
completed = y.Descendants("Name").FirstOrDefault().Attribute("Completed") == null ? false :
((int)y.Descendants("Name").FirstOrDefault().Attribute("Completed")) == 0 ? false : true
}).ToList()
}).SelectMany(x => x.items).ToList();
}
}
public struct Assignment
{
public string name { get; set; }
public DateTime date { get; set; }
public string counsel { get; set; }
public string nextCounsil { get; set; }
public Boolean completed { get; set; }
public string _type { get; set; }
}
}