我刚刚发表了一篇关于如何做的CodeProject文章。本文提供了一个小巧的C#DispatchUtility
辅助类,它很容易包含在其他项目中。在内部,它使用IDispatch和.NET的TypeToTypeInfoMarshaler的自定义声明将IDispatch的ITypeInfo转换为丰富的.NET Type实例。
在你的例子中,你可以调用DispatchUtility.GetType(obj, true)
来取回一个.NET Type实例,然后你可以调用GetMembers。
FWIW,DispatchUtility
对IDispatch.GetTypeInfo的声明与您的声明几乎完全相同。但是,在调用GetTypeInfo时,它会传递LOCALE_SYSTEM_DEFAULT(2048)而不是0作为lcid参数。也许GetTypeInfo为您的disp.GetTypeInfo(0, 0, out t)
调用返回了失败HRESULT。既然你用[PreserveSig]
来声明它,你需要检查它的结果(例如,通过调用Marshal.ThrowExceptionForHR
)。
这里的DispatchUtility
类评论最多的去除的一个版本:
using System;
using System.Runtime.InteropServices;
using System.Reflection;
public static class DispatchUtility
{
private const int S_OK = 0; //From WinError.h
private const int LOCALE_SYSTEM_DEFAULT = 2 << 10; //From WinNT.h == 2048 == 0x800
public static bool ImplementsIDispatch(object obj)
{
bool result = obj is IDispatchInfo;
return result;
}
public static Type GetType(object obj, bool throwIfNotFound)
{
RequireReference(obj, "obj");
Type result = GetType((IDispatchInfo)obj, throwIfNotFound);
return result;
}
public static bool TryGetDispId(object obj, string name, out int dispId)
{
RequireReference(obj, "obj");
bool result = TryGetDispId((IDispatchInfo)obj, name, out dispId);
return result;
}
public static object Invoke(object obj, int dispId, object[] args)
{
string memberName = "[DispId=" + dispId + "]";
object result = Invoke(obj, memberName, args);
return result;
}
public static object Invoke(object obj, string memberName, object[] args)
{
RequireReference(obj, "obj");
Type type = obj.GetType();
object result = type.InvokeMember(memberName,
BindingFlags.InvokeMethod | BindingFlags.GetProperty,
null, obj, args, null);
return result;
}
private static void RequireReference<T>(T value, string name) where T : class
{
if (value == null)
{
throw new ArgumentNullException(name);
}
}
private static Type GetType(IDispatchInfo dispatch, bool throwIfNotFound)
{
RequireReference(dispatch, "dispatch");
Type result = null;
int typeInfoCount;
int hr = dispatch.GetTypeInfoCount(out typeInfoCount);
if (hr == S_OK && typeInfoCount > 0)
{
dispatch.GetTypeInfo(0, LOCALE_SYSTEM_DEFAULT, out result);
}
if (result == null && throwIfNotFound)
{
// If the GetTypeInfoCount called failed, throw an exception for that.
Marshal.ThrowExceptionForHR(hr);
// Otherwise, throw the same exception that Type.GetType would throw.
throw new TypeLoadException();
}
return result;
}
private static bool TryGetDispId(IDispatchInfo dispatch, string name, out int dispId)
{
RequireReference(dispatch, "dispatch");
RequireReference(name, "name");
bool result = false;
Guid iidNull = Guid.Empty;
int hr = dispatch.GetDispId(ref iidNull, ref name, 1, LOCALE_SYSTEM_DEFAULT, out dispId);
const int DISP_E_UNKNOWNNAME = unchecked((int)0x80020006); //From WinError.h
const int DISPID_UNKNOWN = -1; //From OAIdl.idl
if (hr == S_OK)
{
result = true;
}
else if (hr == DISP_E_UNKNOWNNAME && dispId == DISPID_UNKNOWN)
{
result = false;
}
else
{
Marshal.ThrowExceptionForHR(hr);
}
return result;
}
[ComImport]
[InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
[Guid("00020400-0000-0000-C000-000000000046")]
private interface IDispatchInfo
{
[PreserveSig]
int GetTypeInfoCount(out int typeInfoCount);
void GetTypeInfo(int typeInfoIndex, int lcid, [MarshalAs(UnmanagedType.CustomMarshaler,
MarshalTypeRef = typeof(System.Runtime.InteropServices.CustomMarshalers.TypeToTypeInfoMarshaler))] out Type typeInfo);
[PreserveSig]
int GetDispId(ref Guid riid, ref string name, int nameCount, int lcid, out int dispId);
// NOTE: The real IDispatch also has an Invoke method next, but we don't need it.
}
}
谢谢。事实上,这个组件是一个内置脚本语言的商业应用程序。其成员的完整列表在运行时确定。它没有类型库。 – 2010-11-13 06:45:31
@HansPassant我碰到了这里的腥第三个参数的解释:https://www.codeproject.com/articles/523417/reflection-with-idispatch-based-com-objects – jnm2 2017-02-11 13:41:13