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using System;
using System.Security.Permissions;
namespace System.Runtime.InteropServices {
[System.Security.SecuritySafeCritical]
public class ComAwareEventInfo : System.Reflection.EventInfo {
#region private fields
private System.Reflection.EventInfo _innerEventInfo;
#endregion
#region ctor
public ComAwareEventInfo(Type type, string eventName) {
_innerEventInfo = type.GetEvent(eventName);
}
#endregion
#region protected overrides
#if FEATURE_NETCORE
[System.Security.SecuritySafeCritical]
#endif//FEATURE_NETCORE
public override void AddEventHandler(object target, Delegate handler) {
if (Marshal.IsComObject(target)) {
// retrieve sourceIid and dispid
Guid sourceIid;
int dispid;
GetDataForComInvocation(_innerEventInfo, out sourceIid, out dispid);
#if FEATURE_CAS_POLICY
// now validate the caller can call into native and redirect to ComEventHelpers.Combine
SecurityPermission perm = new SecurityPermission(SecurityPermissionFlag.UnmanagedCode);
perm.Demand();
#endif//FEATURE_CAS_POLICY
System.Runtime.InteropServices.ComEventsHelper.Combine(target, sourceIid, dispid, handler);
} else {
// we are dealing with a managed object - just add the delegate through reflection
_innerEventInfo.AddEventHandler(target, handler);
}
}
#if FEATURE_NETCORE
[System.Security.SecuritySafeCritical]
#endif//FEATURE_NETCORE
public override void RemoveEventHandler(object target, Delegate handler) {
if (Marshal.IsComObject(target)) {
// retrieve sourceIid and dispid
Guid sourceIid;
int dispid;
GetDataForComInvocation(_innerEventInfo, out sourceIid, out dispid);
#if FEATURE_CAS_POLICY
// now validate the caller can call into native and redirect to ComEventHelpers.Combine
SecurityPermission perm = new SecurityPermission(SecurityPermissionFlag.UnmanagedCode);
perm.Demand();
#endif//FEATURE_CAS_POLICY
System.Runtime.InteropServices.ComEventsHelper.Remove(target, sourceIid, dispid, handler);
} else {
// we are dealing with a managed object - just add the delegate through relection
_innerEventInfo.RemoveEventHandler(target, handler);
}
}
#endregion
#region public overrides
public override System.Reflection.EventAttributes Attributes {
get { return _innerEventInfo.Attributes; }
}
public override System.Reflection.MethodInfo GetAddMethod(bool nonPublic) {
return _innerEventInfo.GetAddMethod(nonPublic);
}
public override System.Reflection.MethodInfo GetRaiseMethod(bool nonPublic) {
return _innerEventInfo.GetRaiseMethod(nonPublic);
}
public override System.Reflection.MethodInfo GetRemoveMethod(bool nonPublic) {
return _innerEventInfo.GetRemoveMethod(nonPublic);
}
public override Type DeclaringType {
get { return _innerEventInfo.DeclaringType; }
}
public override object[] GetCustomAttributes(Type attributeType, bool inherit) {
return _innerEventInfo.GetCustomAttributes(attributeType, inherit);
}
public override object[] GetCustomAttributes(bool inherit) {
return _innerEventInfo.GetCustomAttributes(inherit);
}
public override bool IsDefined(Type attributeType, bool inherit) {
return _innerEventInfo.IsDefined(attributeType, inherit);
}
public override string Name {
get { return _innerEventInfo.Name; }
}
public override Type ReflectedType {
get { return _innerEventInfo.ReflectedType; }
}
#endregion
#region private methods
private static void GetDataForComInvocation(System.Reflection.EventInfo eventInfo, out Guid sourceIid, out int dispid) {
object[] comEventInterfaces = eventInfo.DeclaringType.GetCustomAttributes(typeof(ComEventInterfaceAttribute), false);
if (comEventInterfaces == null || comEventInterfaces.Length == 0) {
//
throw new InvalidOperationException("event invocation for COM objects requires interface to be attributed with ComSourceInterfaceGuidAttribute");
}
if (comEventInterfaces.Length > 1) {
//
throw new System.Reflection.AmbiguousMatchException("more than one ComSourceInterfaceGuidAttribute found");
}
Type sourceItf = ((ComEventInterfaceAttribute)comEventInterfaces[0]).SourceInterface;
Guid guid = sourceItf.GUID;
System.Reflection.MethodInfo methodInfo = sourceItf.GetMethod(eventInfo.Name);
Attribute dispIdAttribute = Attribute.GetCustomAttribute(methodInfo, typeof(DispIdAttribute));
if (dispIdAttribute == null) {
//
throw new InvalidOperationException("event invocation for COM objects requires event to be attributed with DispIdAttribute");
}
sourceIid = guid;
dispid = ((DispIdAttribute)dispIdAttribute).Value;
}
#endregion
}
}
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