问题描述
请参阅第一个编辑（底部的屏幕截图）：
我已按照此文章使Winform应用触发VSTO加载项方法：
在上面的文章结束时，作者提到一个问题，并尝试在这里改进它：
我已通过代码多次现在和导出StandardOleMarshalObject以改善异常的方法不起作用
System.InvalidCastException：无法将类型为System .__ ComObject的COM对象转换为接口类型...此操作失败，因为COM组件上的QueryInterface调用与IID
这里是两个项目目标.Net 3.5：
a）创建一个新的Office> 2007或2010> Excel加载项： / p>
命名空间ExcelAddIn1
{
public partial class ThisAddIn
{
private AddinUtilities addinUtilities ;
protected override object RequestComAddInAutomationService（）
{
if（addinUtilities == null）
{
addinUtilities = new AddinUtilities
}
return addinUtilities;
}
private void ThisAddIn_Startup（object sender，System.EventArgs e）
{
}
private void ThisAddIn_Shutdown（object sender，System.EventArgs e）
{
}
}
}
类加载到Excel加载项：
命名空间ExcelAddIn1
{
[ComVisible（true）]
[InterfaceType（ComInterfaceType.InterfaceIsDual）]
public interface IAddinUtilities
{
void DisplayMessage（）;
}
[ComVisible（true）]
[ClassInterface（ClassInterfaceType.None）]
public class AddinUtilities：
StandardOleMarshalObject，
IAddinUtilities
{
void IAddinUtilities.DisplayMessage（）
{
MessageBox.Show（Hello World）;
}
}
}
Build> seklect注册COM Interop。编译加载项。
d）新的Winform应用程序，引用ExcelAddIn1，Microsoft.Office.Interop.Excel和Office，并将此代码包含在Form1中：
public partial class Form1：Form
{
private Microsoft.Office.Interop.Excel.Application excel;
private IAddinUtilities utils;
public Form1（）
{
InitializeComponent（）;
}
private void Form1_Load（object sender，EventArgs e）
{
excel = new Microsoft.Office.Interop.Excel.Application（）;
excel.Visible = true;
excel.Workbooks.Add（Microsoft.Office.Interop.Excel.XlSheetType.xlWorksheet）;
object addinName =ExcelAddin1;
COMAddIn addin = excel.COMAddIns.Item（ref addinName）;
utils =（IAddinUtilities）addin.Object;
utils.DisplayMessage（）;
}
}
e）运行Winform应用程序， c $ c> utils =（IAddinUtilities）addin.Object; 失败，无论AddinUtilities是否派生自StandardOleMarshalObject。
由于MSDN Blog明确地说：要解决这一切，你可以从StandardOleMarshalObject派生AddinUtilities类，并重建：
p> 1st EDIT：我尝试在另一个PC-B上的代码，它的工作原理不是从 StandardOleMarshalObject ，
当我在PC-B上使用 StandardOleMarshalObject 时，我遇到了与PC-A相同的问题。 PC-A不工作与任何方式，唯一的区别，我可以想到的是管理员权限。
>
管理员权限和pre-Win7（旧的msdn文章）是我能想到为什么它不工作的唯一原因。
当设置注册Com interop 我发现你需要以管理员身份运行 / p>
如果没有管理员尝试编译，我会收到以下错误：
上面的注册表项不存在，所以我创建它，然后尝试编译我得到：
解决方案
关闭注册COM interop并且错误消失 - 但是这导致它不工作！
Shift +右键单击Visual Studio并以管理员身份打开该项目。 Tick注册Com互操作，它编译成功，它现在工作在PC-A当从StandardOleMarshalObject - ，但它不工作没有StandardOleMarshalObject - 这是相反的结果，我在PC-B 。
Please see 1st Edit (the screenshot at the bottom):
I've followed this article to have a Winform app trigger a VSTO Add-In method:http://blogs.msdn.com/b/andreww/archive/2007/01/15/vsto-add-ins-comaddins-and-requestcomaddinautomationservice.aspx
At the end of the above article the author mentions a issue and tries to ameliorate it here:http://blogs.msdn.com/b/andreww/archive/2008/08/11/why-your-comaddin-object-should-derive-from-standardolemarshalobject.aspx
I have been through the code several times now and the method to derive StandardOleMarshalObject to ameliorate the exception does not work!
System.InvalidCastException: Unable to cast COM object of type 'System.__ComObject' to interface type ... This operation failed because the QueryInterface call on the COM component for the interface with IID
Here is a repro - both projects target .Net 3.5:
a) Create a new Office > 2007 or 2010 > Excel Add-In:
namespace ExcelAddIn1
{
public partial class ThisAddIn
{
private AddinUtilities addinUtilities;
protected override object RequestComAddInAutomationService()
{
if (addinUtilities == null)
{
addinUtilities = new AddinUtilities();
}
return addinUtilities;
}
private void ThisAddIn_Startup(object sender, System.EventArgs e)
{
}
private void ThisAddIn_Shutdown(object sender, System.EventArgs e)
{
}
}
}
b) Add a class to the Excel Add-In:
namespace ExcelAddIn1
{
[ComVisible(true)]
[InterfaceType(ComInterfaceType.InterfaceIsDual)]
public interface IAddinUtilities
{
void DisplayMessage();
}
[ComVisible(true)]
[ClassInterface(ClassInterfaceType.None)]
public class AddinUtilities :
StandardOleMarshalObject,
IAddinUtilities
{
void IAddinUtilities.DisplayMessage()
{
MessageBox.Show("Hello World");
}
}
}
c) Set Project Properties > Build > seklect Register For COM Interop. Compile the Add-In.
d) New Winform App, reference the ExcelAddIn1, Microsoft.Office.Interop.Excel and Office and include this code in Form1:
public partial class Form1 : Form
{
private Microsoft.Office.Interop.Excel.Application excel;
private IAddinUtilities utils;
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
excel = new Microsoft.Office.Interop.Excel.Application();
excel.Visible = true;
excel.Workbooks.Add(Microsoft.Office.Interop.Excel.XlSheetType.xlWorksheet);
object addinName = "ExcelAddin1";
COMAddIn addin = excel.COMAddIns.Item(ref addinName);
utils = (IAddinUtilities)addin.Object;
utils.DisplayMessage();
}
}
e) Run the Winform app and the line utils = (IAddinUtilities)addin.Object; fails regardless of whether or not AddinUtilities derives from StandardOleMarshalObject.
I am at a loss here as the MSDN Blog specifically says: "To fix all this, you can simply derive the AddinUtilities class from StandardOleMarshalObject, and rebuild:"
1st EDIT: I tried the code on another PC-B and it works without deriving from StandardOleMarshalObject,
When I tried with StandardOleMarshalObject on PC-B I got the same problem as PC-A. PC-A doesn't work with either ways and the only difference I can think of is admin rights.
Admin rights and pre-Win7 (old msdn articles) are the only reasons I can think of why it would not work.
When setting Register For Com interop I've found that you do need to run as Administrator.
Without Administrator trying to compile I got errors like:
The above registry key didn't exist so I created it, then trying to compile I got:
Solution
Turn off Register for COM interop and the error goes away - but this causes it not to work!
Shift + Right click Visual Studio and open as Administrator, open the project. Tick Register for Com interop and it compiles successfully and it works now on PC-A when deriving from StandardOleMarshalObject - but it doesn't work without StandardOleMarshalObject - which is the opposite results I got on PC-B.
这篇关于VSTO加载项，COMAddIns和RequestComAddInAutomationService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！