问题描述

我正在尝试从 .NET 程序集中返回一组部门，以供 ASP 通过 COM 互操作使用.使用 .NET 我只会返回一个通用集合，例如List<Department>，但泛型似乎不适用于 COM 互操作.那么，我有哪些选择?

I am attempting to return a collection of departments from a .NET assembly to be consumed by ASP via COM Interop. Using .NET I would just return a generic collection, e.g. List<Department>, but it seems that generics don't work well with COM Interop. So, what are my options?

我想遍历列表并能够按索引访问项目.我应该从 List 继承，实现 IList、IList 或其他接口，还是有更好的方法?理想情况下，我宁愿不必为我需要的每种类型的列表实现自定义集合.此外，List[index] 甚至可以与 COM Interop 一起使用吗?

I would like to both iterate over the list and be able to access an item by index. Should I inherit from List<Department>, implement an IList, IList<Department> or another interface, or is there a better way? Ideally I would prefer not to have to implement a custom collection for every type of list I need. Also, will List[index] even work with COM Interop?

谢谢，迈克

public class Department {
    public string Code { get; private set; }
    public string Name { get; private set; }
    // ...
}

public class MyLibrary {
    public List<Department> GetDepartments() {
        // return a list of Departments from the database
    }
}

示例 ASP 代码:

<%
Function PrintDepartments(departments)
    Dim department
    For Each department In departments
        Response.Write(department.Code & ": " & department.Name & "<br />")
    Next
End Function

Dim myLibrary, departments
Set myLibrary = Server.CreateObject("MyAssembly.MyLibrary")
Set departments = myLibrary.GetDepartments()
%>
<h1>Departments</h1>
<% Call PrintDepartments(departments) %>
<h1>The third department</h1>
<%= departments(2).Name %>

相关问题:

• 在服务组件上使用通用列表
• .NET 中的非泛型集合是否已过时?

推荐答案

经过更多的研究和反复试验，我想我找到了使用 System.Collections.ArrayList 的解决方案.但是，这不适用于按索引获取值.为此，我创建了一个继承自 ArrayList 的新类 ComArrayList，并添加了新方法 GetByIndex 和 SetByIndex.

After some more research and trial-and-error, I think I found a solution by using System.Collections.ArrayList. However, this does not work with getting a value by index. To do so, I created a new class ComArrayList that inherits from ArrayList and adds new methods GetByIndex and SetByIndex.

public class ComArrayList : System.Collections.ArrayList {
    public virtual object GetByIndex(int index) {
        return base[index];
    }

    public virtual void SetByIndex(int index, object value) {
        base[index] = value;
    }
}

更新了 .NET 组件 MyLibrary.GetDepartments:

public ComArrayList GetDepartments() {
    // return a list of Departments from the database
}

更新的 ASP:

<h1>The third department</h1>
<%= departments.GetByIndex(2).Name %>

这篇关于COM 互操作的通用集合的替代方案是什么?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持编程学习网！