如何从 .NET 设置 COM+ 组件的构造函数字符串？

Question

我正在尝试从 C# 应用程序以编程方式设置 COM+ 组件的构造函数字符串。我在网上找到了下面的示例代码，但是它抛出了一个异常：

        COMAdminCatalogCollection Components;
        COMAdminCatalogClass Catalog = new COMAdminCatalogClass();
        string strConstr;
        string ApplicationName = "ApplicationName"; // case sensitive
        string CompName = "MyComponent.ProgID";
        COMAdminCatalogCollectionClass Applications = (COMAdminCatalogCollectionClass)Catalog.GetCollection("Applications");
        Applications.Populate();
        // find the correct application
        foreach (COMAdminCatalogObjectClass AppObject in Applications)
        {
            if (AppObject.Name == ApplicationName)
            {
                // find matching component
                Components = (COMAdminCatalogCollectionClass)(Applications.GetCollection("Components", AppObject.Key));
                Components.Populate();
                foreach (COMAdminCatalogObjectClass CompObject in Components)
                {
                    if (CompObject.Name.ToString() == CompName)
                    {
                        CompObject.get_Value("ConstructorString").ToString();
                        CompObject.get_Value("ConstructionEnabled").ToString();
                    }
                }
            }
        }

当我运行此代码时，我在第 6 行得到以下异常：

无法将类型为“System.__ComObject”的 COM 对象转换为类类型“COMAdmin.COMAdminCatalogCollectionClass”。进入 CLR 且不支持 IProvideClassInfo 或未注册任何互操作程序集的 COM 组件将包装在 __ComObject 类型中。这种类型的实例不能转换为任何其他类；但是，只要底层 COM 组件支持对接口的 IID 的 QueryInterface 调用，它们就可以转换为接口。

知道我哪里出错了吗？或者有更简单的方法吗？

Answer 1

我找到了避免异常的方法。我可以利用 VB.NET 的可选弱类型来删除所有强制转换和几个变量声明类型，而不是在 C# 中执行此操作。生成的代码如下所示：

    Dim Components As COMAdminCatalogCollection
    Dim Catalog As New COMAdminCatalogClass()
    Dim ApplicationName As String = "ApplicationName"
    Dim CompName As String = "MyComponent.ProgID"
    Dim Applications = Catalog.GetCollection("Applications")
    Applications.Populate()
    For Each AppObject In Applications

        If (AppObject.Name = ApplicationName) Then

            Components = (Applications.GetCollection("Components", AppObject.Key))
            Components.Populate()
            For Each CompObject In Components

                If (CompObject.Name.ToString() = CompName) Then
                    CompObject.Value("ConstructorString") = "Some new value"

                    Components.SaveChanges()
                End If

            Next
        End If
    Next

这是 VB 和 C# 显着不同的一种情况，了解这些内容确实有助于您为工作选择正确的工具。

Answer 2

我确信你已经顺利通过了这个，但我目前正在开发一个需要类似功能的项目，我能够使用 .NET 和 PowerShell 提出一个解决方案来做到这一点。首先，我在 C# 中创建了一个自定义 cmdlet，如下所示：

using COMAdmin;
using System;
using System.Runtime.InteropServices;
using System.Management.Automation;

namespace COMAdminModule
{
    // Name the cmdlet
    [Cmdlet("Set", "COMConstructorString")]
    public class SetCOMConstructorSting : PSCmdlet
    {

        // App name Parameter
        private string comAppName;

        [Parameter(
            Mandatory = true,
            ValueFromPipelineByPropertyName = true,
            ValueFromPipeline = true,
            Position = 0,
            HelpMessage = "Name of COM+ Application"
            )]

        [Alias("App Name")]


        public string COMApp
        {
            get { return comAppName; }
            set { comAppName = value; }
        }


        // App Component name
        private string componentName;

        [Parameter(
            Mandatory = true,
            ValueFromPipelineByPropertyName = true,
            ValueFromPipeline = true,
            Position = 1,
            HelpMessage = "The name of the Component that will receive a new Constructor string"
            )]

        [Alias("Component Name")]


        public string ComponentName
        {
            get { return componentName; }
            set { componentName = value; }
        }


        // Constructor String
        private string constructorString;

        [Parameter(
            Mandatory = true,
            ValueFromPipelineByPropertyName = true,
            ValueFromPipeline = true,
            Position = 2,
            HelpMessage = "The new Constructor string"
            )]

        [Alias("Constructor String")]


        public string ConstructorString
        {
            get { return constructorString; }
            set { constructorString = value; }
        }


        // Provides a one-time, preprocessing functionality for the cmdlet
        protected override void BeginProcessing()
        {
            base.BeginProcessing();
        }

        // Provides a record-by-record processing functionality for the cmdlet
        protected override void ProcessRecord()
        {
            string working = "Setting the constructor string " + constructorString;
            working = " to the Component " + componentName;
            working += " for the COM App " + comAppName;

            WriteObject(working);

            setConstructorString(comAppName, componentName, constructorString);
        }

        // Provides a one-time, post-processing functionality for the cmdlet
        protected override void EndProcessing()
        {
            base.EndProcessing();
        }




        //Add component method
        private void setConstructorString(string comAppName, string componentName, string constructorString)
        {
            ICOMAdminCatalog2 oCatalog = null;

            try
            {

                //Create the comAdmin object
                oCatalog = (ICOMAdminCatalog2)Activator.CreateInstance(Type.GetTypeFromProgID("ComAdmin.COMAdminCatalog"));

                //Get the comApps
                ICatalogCollection comApps = (ICatalogCollection)oCatalog.GetCollection("Applications");
                comApps.Populate();


                foreach (ICatalogObject app in comApps)
                {

                    //Find the comApp
                    if (app.Name.ToString().Equals(comAppName))
                    {
                        //Get the Components
                        ICatalogCollection components = (ICatalogCollection)comApps.GetCollection("Components", app.Key);
                        components.Populate();


                        foreach (ICatalogObject component in components) 
                        {
                            //Find the component
                            if (component.Name.ToString().Equals(componentName))
                            {
                                // Set the constructor string
                                component.set_Value("ConstructorString", constructorString);

                                components.SaveChanges();

                                break;
                            }

                        }

                        break; 
                    }

                }

            }
            catch (Exception e)
            {
                WriteObject(e.Source);
                throw;
            }
        }
    }
}

然后将该模块导入 PowerShell 脚本并按如下方式运行：

PS C:\Windows\system32> Import-Module "<dll path>"

PS C:\Windows\system32> Set-COMConstructorString <Application Name> <Component Name> <Constructor String>