115 lines
4.1 KiB
C#
115 lines
4.1 KiB
C#
// ==++==
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//
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// Copyright (c) Microsoft Corporation. All rights reserved.
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//
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// ==--==
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// This class represents the Ole Automation binder.
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// #define DISPLAY_DEBUG_INFO
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namespace System {
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using System;
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using System.Runtime.InteropServices;
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using System.Reflection;
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using Microsoft.Win32;
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using CultureInfo = System.Globalization.CultureInfo;
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// Made serializable in anticipation of this class eventually having state.
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[Serializable]
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internal class OleAutBinder : DefaultBinder
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{
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// ChangeType
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// This binder uses OLEAUT to change the type of the variant.
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[System.Security.SecuritySafeCritical] // overrides transparent member
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public override Object ChangeType(Object value, Type type, CultureInfo cultureInfo)
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{
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Variant myValue = new Variant(value);
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if (cultureInfo == null)
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cultureInfo = CultureInfo.CurrentCulture;
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#if DISPLAY_DEBUG_INFO
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Console.WriteLine("In OleAutBinder::ChangeType converting variant of type: {0} to type: {1}", myValue.VariantType, type.Name);
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#endif
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if (type.IsByRef)
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{
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#if DISPLAY_DEBUG_INFO
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Console.WriteLine("Stripping byref from the type to convert to.");
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#endif
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type = type.GetElementType();
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}
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// If we are trying to convert from an object to another type then we don't
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// need the OLEAUT change type, we can just use the normal COM+ mechanisms.
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if (!type.IsPrimitive && type.IsInstanceOfType(value))
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{
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#if DISPLAY_DEBUG_INFO
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Console.WriteLine("Source variant can be assigned to destination type");
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#endif
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return value;
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}
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Type srcType = value.GetType();
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// Handle converting primitives to enums.
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if (type.IsEnum && srcType.IsPrimitive)
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{
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#if DISPLAY_DEBUG_INFO
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Console.WriteLine("Converting primitive to enum");
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#endif
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return Enum.Parse(type, value.ToString());
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}
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#if !FEATURE_CORECLR
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// Special case the convertion from DBNull.
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if (srcType == typeof(DBNull))
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{
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// The requested type is a DBNull so no convertion is required.
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if (type == typeof(DBNull))
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return value;
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// Visual J++ supported converting from DBNull to null so customers
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// have requested (via a CDCR) that DBNull be convertible to null.
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// We don't however allow this when converting to a value class, since null
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// doesn't make sense for these, or to object since this would change existing
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// semantics.
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if ((type.IsClass && type != typeof(Object)) || type.IsInterface)
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return null;
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}
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#endif //!FEATURE_CORECLR
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// Use the OA variant lib to convert primitive types.
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try
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{
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#if DISPLAY_DEBUG_INFO
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Console.WriteLine("Using OAVariantLib.ChangeType() to do the conversion");
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#endif
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// Specify the LocalBool flag to have BOOL values converted to local language rather
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// than 0 or -1.
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Object RetObj = OAVariantLib.ChangeType(myValue, type, OAVariantLib.LocalBool, cultureInfo).ToObject();
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#if DISPLAY_DEBUG_INFO
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Console.WriteLine("Object returned from ChangeType is of type: " + RetObj.GetType().Name);
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#endif
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return RetObj;
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}
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#if DISPLAY_DEBUG_INFO
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catch(NotSupportedException e)
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#else
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catch(NotSupportedException)
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#endif
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{
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#if DISPLAY_DEBUG_INFO
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Console.Write("Exception thrown: ");
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Console.WriteLine(e);
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#endif
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throw new COMException(Environment.GetResourceString("Interop.COM_TypeMismatch"), unchecked((int)0x80020005));
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}
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}
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}
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}
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