ComAwareEventInfo.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / System / Runtime / InteropServices / ComAwareEventInfo.cs / 1305376 / ComAwareEventInfo.cs
                        
                        
                            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
        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); 

                // now validate the caller can call into native and redirect to ComEventHelpers.Combine 
                SecurityPermission perm = new SecurityPermission(SecurityPermissionFlag.UnmanagedCode);
                perm.Demand();
                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); 
            } 
        }
 
        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); 
 
                // now validate the caller can call into native and redirect to ComEventHelpers.Combine
                SecurityPermission perm = new SecurityPermission(SecurityPermissionFlag.UnmanagedCode); 
                perm.Demand();
                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
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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ComAwareEventInfo.cs source code in C# .NET

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