ErrorWrapper Class
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ErrorWrapper Class

 

Wraps objects the marshaler should marshal as a VT_ERROR.

Namespace:   System.Runtime.InteropServices
Assembly:  mscorlib (in mscorlib.dll)

System.Object
  System.Runtime.InteropServices.ErrorWrapper

[<Sealed>]
[<SerializableAttribute>]
[<ComVisibleAttribute(true)>]
type ErrorWrapper = class end

NameDescription
System_CAPS_pubmethodErrorWrapper(Exception)

Initializes a new instance of the ErrorWrapper class with the HRESULT that corresponds to the exception supplied.

System_CAPS_pubmethodErrorWrapper(Int32)

Initializes a new instance of the ErrorWrapper class with the HRESULT of the error.

System_CAPS_pubmethodErrorWrapper(Object)

Initializes a new instance of the ErrorWrapper class with an object containing the HRESULT of the error.

NameDescription
System_CAPS_pubpropertyErrorCode

Gets the error code of the wrapper.

NameDescription
System_CAPS_pubmethodEquals(Object)

Determines whether the specified object is equal to the current object.(Inherited from Object.)

System_CAPS_pubmethodGetHashCode()

Serves as the default hash function. (Inherited from Object.)

System_CAPS_pubmethodGetType()

Gets the Type of the current instance.(Inherited from Object.)

System_CAPS_pubmethodToString()

Returns a string that represents the current object.(Inherited from Object.)

By default, Object type arguments are marshaled as a VARIANT type, where the object type determines the VARTYPE value of the VARIANT.

The ErrorWrapper type must to be passed as an Object type to be marshaled as a VARIANT of type VT_ERROR, otherwise the ErrorWrapper type is marshaled as an integer.

The following table illustrates marshaling in a managed call to a native function, using platform invoke.

Managed signature parameter

pArr value

Marshaled as

ErrorWrapper[] pArr

ErrorWrapper[10] of ErrorWrapper(77)

Int[10]

Object[] pArr

ErrorWrapper[10] of ErrorWrapper(77)

VARIANT[10] of VT_ERROR

Object[] pArr

Object[10] of ErrorWrapper(77)

VARIANT[10] of VT_ERROR

The following table illustrates marshaling data in a managed call to a native function, using COM runtime callable wrappers (RCW).

Managed signature parameter

pArr value

Marshaled as

ErrorWrapper[] pArr

ErrorWrapper[10] of ErrorWrapper(77)

Int[10]

Object[] pArr

ErrorWrapper[10] of ErrorWrapper(77)

SafeArrayTypeMismatch exception

Object[] pArr

Object[10] of ErrorWrapper(77)

SAFEARRAY(VARIANT)

Note that ErrorWrapper objects are not marshaled as type VT_ERROR after they are passed back from COM. A single value is marshaled back from COM as type VT_I4, while arrays are marshaled back from COM as type VT_UI4.

For more information on VT_ERROR, please see the existing documentation for VARENUM::VT_ERROR in the MSDN library.

The following code example first demonstrates a lone Int32 object marshaled back from COM as an Int32 object. It then demonstrates an Int32 array marshaled back from COM as a UInt32 array.

// Scenario 1:
// Pass a single value.
Int32 x = 3;
Object o = new ErrorWrapper(x);
// Pass 'o' to COM.
// On the return trip, 'o' has been unwrapped and is still an Int32 object.
Int32 y = (Int32)o;
Scenario 2:
// Pass an array of values.
Int32[] arr = new Int32[3];
Object o = new ErrorWrapper(arr);
// Pass 'o' to COM.
// On the return trip, 'o' has been unwrapped and is now a UInt32[] array.
UInt32[ ] arr2 = (UInt32[])o;

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Windows Phone
Available since 8.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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