Obtención de valores locales
Importante
En Visual Studio 2015, esta forma de implementar evaluadores de expresiones está en desuso. Para obtener información sobre cómo implementar evaluadores de expresiones CLR, vea Evaluadores de expresiones CLR y Ejemplo de evaluador de expresiones administradas.
Para obtener el valor de una instancia local, Visual Studio llama a GetPropertyInfo para esa configuración local. En esta implementación, la clase CFieldProperty implementa la interfaz IDebugProperty2 para cada local.
Esta implementación de IDebugProperty2::GetPropertyInfo realiza las siguientes tareas:
Obtiene el nombre, la propiedad y los atributos locales de la estructura FIELD_INFO rellenada cuando se creó una instancia de la clase e inicializó.
Obtiene el tipo del local del objeto IDebugField .
Obtiene el valor
IDebugFielddel objeto local. Este campo está enlazado a la ubicación de memoria del local mediante el objeto IDebugBinder y el valor se obtiene del objeto IDebugObject resultante.Devuelve todas las propiedades solicitadas en una estructura de DEBUG_PROPERTY_INFO .
Código administrado
En este ejemplo se muestra una implementación de para el local de IDebugProperty2::GetPropertyInfo un método en código administrado. También muestra una función auxiliar, , Field.GetTypeque se usa para obtener el tipo del campo. Field.GetValue se muestra en Evaluar variables locales. La función Field.MapModifiersToAttributes auxiliar (no se muestra) simplemente convierte las marcas de FIELD_MODIFIERS de un campo en DBG_ATTRIB_FLAGS valores.
namespace EEMC
{
public class CFieldProperty : IDebugProperty2
{
public HRESULT GetPropertyInfo(
uint dwFields,
uint radix,
uint timeout,
IDebugReference2[] refArgs,
uint argCount,
DEBUG_PROPERTY_INFO[] infoArray)
{
DEBUGPROP_INFO_FLAGS flags = (DEBUGPROP_INFO_FLAGS) dwFields;
DEBUGPROP_INFO_FLAGS infoFields = DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_NONE;
// Initialize the structure.
DEBUG_PROPERTY_INFO info = infoArray[0];
info.pProperty = null;
// Fill in the full name, if requested.
if (0 != (flags & DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_FULLNAME))
{
info.bstrFullName = fieldInfo.bstrFullName;
infoFields |= DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_FULLNAME;
}
// Fill in the name, if requested.
if (0 != (flags & DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_NAME))
{
info.bstrName = fieldInfo.bstrName;
infoFields |= DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_NAME;
}
// Fill in the type, if requested.
if (0 != (flags & DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_TYPE))
{
if (fieldType == null)
fieldType = Field.GetType(field, out fieldSize);
if (fieldType == null)
info.bstrType = "unknown";
else
info.bstrType = fieldType.ToString();
infoFields |= DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_TYPE;
}
// The property associated with this property is this property.
if (0 != (flags & DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_PROP))
{
info.pProperty = this;
infoFields |= DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_PROP;
}
// Get the property value, if requested.
if (0 != (flags & DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_VALUE))
{
if (fieldType == null)
fieldType = Field.GetType(field, out fieldSize);
if (fieldType == null)
info.bstrValue = "?";
else
{
object o = Field.GetValue(binder, field, fieldType, fieldSize);
if (o == null)
info.bstrValue = "?";
else
info.bstrValue = o.ToString();
}
infoFields |= DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_VALUE;
}
// Get the property attributes, if requested.
if (0 != (flags & DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_ATTRIB))
{
info.dwAttrib =
(ulong) Field.MapModifiersToAttributes(
(FIELD_MODIFIERS) fieldInfo.dwModifiers,
fieldKind);
infoFields |= DEBUGPROP_INFO_FLAGS.DEBUGPROP_INFO_ATTRIB;
}
info.dwFields = (uint) infoFields;
infoArray[0] = info;
return COM.S_OK;
}
}
//----------------------------------------------------------------------------
internal class Field
{
internal static Type GetType(IDebugField field, out uint size)
{
size = 0;
IDebugField fieldType = null;
field.GetType(out fieldType);
if (fieldType == null) return null;
// Get field size.
fieldType.GetSize(out size);
// Get approximate type name.
FIELD_INFO[] fieldTypeInfo = new FIELD_INFO[1];
fieldType.GetInfo((uint) FIELD_INFO_FIELDS.FIF_NAME,
fieldTypeInfo);
// Map approximate name to type name.
switch (fieldTypeInfo[0].bstrName)
{
case "whole":
switch (size)
{
case 1: return typeof(sbyte);
case 2: return typeof(short);
case 4: return typeof(int);
case 8: return typeof(long);
}
break;
case "uwhole":
switch (size)
{
case 1: return typeof(byte);
case 2: return typeof(char);
case 4: return typeof(uint);
case 8: return typeof(ulong);
}
break;
case "real":
switch (size)
{
case 4: return typeof(float);
case 8: return typeof(double);
}
break;
case "bool": return typeof(bool);
case "string": return typeof(string);
}
return null;
}
}
Código no administrado
En este ejemplo se muestra una implementación de para el local de IDebugProperty2::GetPropertyInfo un método en código no administrado. También muestra dos funciones auxiliares y FieldGetType FieldGetValue que se usan para obtener el tipo y el valor del campo, respectivamente. Se VARIANTusan para el valor y el tipo del campo, ya que VARIANT pueden controlar una amplia variedad de tipos de valor. En esta implementación, FieldGetValue devuelve un objeto IDebugField que se convierte más adelante en un valor de una llamada a FieldGetPrimitiveValue (que se muestra en Evaluate locals).
STDMETHODIMP CFieldProperty::GetPropertyInfo(
in DEBUGPROP_INFO_FLAGS infoFlags,
in DWORD radix,
in DWORD timeout,
in IDebugReference2** ppargs,
in DWORD argCount,
out DEBUG_PROPERTY_INFO* ppropertyInfo
)
{
if (!ppropertyInfo)
return E_INVALIDARG;
else
memset(ppropertyInfo,0,sizeof(*ppropertyInfo));
if (infoFlags & DEBUGPROP_INFO_FULLNAME)
{
ppropertyInfo->dwFields |= DEBUGPROP_INFO_FULLNAME;
ppropertyInfo->bstrFullName = SysAllocString( m_fieldInfo.bstrFullName );
}
if (infoFlags & DEBUGPROP_INFO_NAME)
{
ppropertyInfo->dwFields |= DEBUGPROP_INFO_NAME;
ppropertyInfo->bstrName = SysAllocString( m_fieldInfo.bstrName );
}
if (infoFlags & DEBUGPROP_INFO_TYPE)
{
ppropertyInfo->dwFields |= DEBUGPROP_INFO_TYPE;
VARIANT type;
if (SUCCEEDED(FieldGetType( m_field, &type )))
{
// Convert the variant's type to a string
VariantTypeToString( type, &(ppropertyInfo->bstrType) );
VariantClear(&type);
}
if (ppropertyInfo->bstrType == NULL)
ppropertyInfo->bstrType = SysAllocString( GetString(IDS_MSG_UNKNOWNTYPE) );
}
if (infoFlags & DEBUGPROP_INFO_PROP)
{
ppropertyInfo->dwFields |= DEBUGPROP_INFO_PROP;
QueryInterface( IID_IDebugProperty2,
reinterpret_cast<void**>(&(ppropertyInfo->pProperty)) );
}
if (infoFlags & DEBUGPROP_INFO_VALUE)
{
ppropertyInfo->dwFields |= DEBUGPROP_INFO_VALUE;
//only show primitive values
VARIANT value;
if (SUCCEEDED(FieldGetValue(m_field, &value)))
{
VariantValueToString( radix, m_binder, value,
&(ppropertyInfo->bstrValue) );
VariantClear(&value);
}
if (ppropertyInfo->bstrValue == NULL)
ppropertyInfo->bstrValue = SysAllocString( GetString(IDS_MSG_UNKNOWNVALUE) );
}
if (infoFlags & DEBUGPROP_INFO_VALUE_AUTOEXPAND)
{
// AUTOEXPAND is ignored in this example
}
if (infoFlags & DEBUGPROP_INFO_ATTRIB)
{
ppropertyInfo->dwFields |= DEBUGPROP_INFO_ATTRIB;
FIELD_MODIFIERS modifiers = m_fieldInfo.dwModifiers;
DBG_ATTRIB_FLAGS attrib = DBG_ATTRIB_NONE;
//access
if (modifiers & FIELD_MOD_ACCESS_PUBLIC)
attrib |= DBG_ATTRIB_ACCESS_PUBLIC;
if (modifiers & FIELD_MOD_ACCESS_PRIVATE)
attrib |= DBG_ATTRIB_ACCESS_PRIVATE;
if (modifiers & FIELD_MOD_ACCESS_PROTECTED)
attrib |= DBG_ATTRIB_ACCESS_PROTECTED;
if (modifiers & FIELD_MOD_FINAL)
attrib |= DBG_ATTRIB_ACCESS_FINAL;
//constant
if (modifiers & FIELD_MOD_CONSTANT)
attrib |= DBG_ATTRIB_VALUE_READONLY;
//storage
if (m_fieldKind & FIELD_SYM_GLOBAL)
attrib |= DBG_ATTRIB_STORAGE_GLOBAL;
if (modifiers & FIELD_MOD_STATIC)
attrib |= DBG_ATTRIB_STORAGE_STATIC;
//type modifier
if (modifiers & FIELD_MOD_VIRTUAL)
attrib |= DBG_ATTRIB_TYPE_VIRTUAL;
if (modifiers & FIELD_MOD_CONSTANT)
attrib |= DBG_ATTRIB_TYPE_CONSTANT;
if (modifiers & FIELD_MOD_SYNCHRONIZED)
attrib |= DBG_ATTRIB_TYPE_SYNCHRONIZED;
if (modifiers & FIELD_MOD_VOLATILE)
attrib |= DBG_ATTRIB_TYPE_VOLATILE;
//type
if (m_fieldKind & FIELD_TYPE_METHOD)
attrib |= DBG_ATTRIB_METHOD;
if (m_fieldKind & FIELD_TYPE_PROP)
attrib |= DBG_ATTRIB_PROPERTY;
if (m_fieldKind & FIELD_TYPE_CLASS)
attrib |= DBG_ATTRIB_CLASS;
if (m_fieldKind & FIELD_TYPE_INTERFACE)
attrib |= DBG_ATTRIB_INTERFACE;
if (m_fieldKind & FIELD_TYPE_INNERCLASS)
attrib |= DBG_ATTRIB_INNERCLASS;
if (m_fieldKind & FIELD_KIND_SYMBOL)
attrib |= DBG_ATTRIB_DATA;
//set the debug attributes
ppropertyInfo->dwAttrib = attrib;
}
return S_OK;
}
//////////////////////////////////////////////////////////////////////
// Helper functions
struct PrimitiveTypeInfo
{
LPCOLESTR pszName;
UINT size;
VARTYPE vt;
};
PrimitiveTypeInfo primitiveTypeTable[] =
{
{ OLE("string"), 0, VT_BSTR },
{ OLE("whole"), 1, VT_I1 },
{ OLE("whole"), 2, VT_I2 },
{ OLE("whole"), 4, VT_I4 },
{ OLE("whole"), 8, VT_I8 },
{ OLE("uwhole"), 1, VT_UI1 },
{ OLE("uwhole"), 2, VT_UI2 },
{ OLE("uwhole"), 4, VT_UI4 },
{ OLE("uwhole"), 8, VT_UI8 },
{ OLE("real"), 4, VT_R4 },
{ OLE("real"), 8, VT_R8 },
{ OLE("bool"), 1, VT_BOOL },
{ OLE("bool"), 2, VT_BOOL },
{ OLE("bool"), 4, VT_BOOL },
{ OLE("System.String"), 0, VT_BSTR },
{ OLE("System.SByte"), 1, VT_I1 },
{ OLE("System.Int16"), 2, VT_I2 },
{ OLE("System.Int32"), 4, VT_I4 },
{ OLE("System.Int64"), 8, VT_I8 },
{ OLE("System.Byte"), 1, VT_UI1 },
{ OLE("System.Char"), 1, VT_UI2 },
{ OLE("System.UInt16"), 2, VT_UI2 },
{ OLE("System.UInt32"), 4, VT_UI4 },
{ OLE("System.UInt64"), 8, VT_UI8 },
{ OLE("System.Single"), 4, VT_R4 },
{ OLE("System.Double"), 8, VT_R8 },
{ OLE("System.Boolean"), 1, VT_BOOL },
{ OLE("System.Boolean"), 2, VT_BOOL },
{ OLE("System.Boolean"), 4, VT_BOOL },
{ NULL, 0, VT_EMPTY }
};
HRESULT FieldGetType( in IDebugField* pfield, out VARIANT* pvarType )
{
HRESULT hr;
if (pfield == NULL)
return E_INVALIDARG;
if (pvarType == NULL)
return E_INVALIDARG;
else
*pvarType = 0;
//get type size and name
DWORD fieldTypeSize;
FIELD_INFO fieldTypeInfo;
IDebugField* pfieldType = NULL;
hr = pfield->GetType( &pfieldType );
if (FAILED(hr))
return hr;
hr = pfieldType->GetSize( &fieldTypeSize );
if (FAILED(hr))
{
pfieldType->Release();
return hr;
}
hr = pfieldType->GetInfo( FIF_NAME, &fieldTypeInfo );
if (FAILED(hr))
{
pfieldType->Release();
return hr;
}
//check for primitive types
memset( pvarType, 0, sizeof(*pvarType) );
VariantInit(pvarType);
for (PrimitiveTypeInfo* pprimTypeInfo = primitiveTypeTable;
pprimTypeInfo->pszName != NULL;
pprimTypeInfo++)
{
if (pprimTypeInfo->size == fieldTypeSize &&
(wcscmp(pprimTypeInfo->pszName,fieldTypeInfo.bstrName) == 0))
{
pvarType->vt = pprimTypeInfo->vt;
break;
}
}
//VT_UNKNOWN is used for all other (structured) types
if (pvarType->vt == VT_EMPTY)
{
pvarType->vt = VT_UNKNOWN;
pvarType->punkVal = pfieldType;
pvarType->punkVal->AddRef();
}
if (fieldTypeInfo.bstrName != NULL)
SysFreeString(fieldTypeInfo.bstrName);
pfieldType->Release();
return S_OK;
}
//----------------------------------------------------------------------------
HRESULT FieldGetValue( in IDebugField* pfield, out VARIANT* pvarValue )
{
if (pvarValue == NULL)
return E_INVALIDARG;
else
*pvarValue = 0;
if (pfield == NULL)
return E_INVALIDARG;
//we delay getting the primitive value by just setting VT_UNKNOWN
pvarValue->vt = VT_UNKNOWN;
pvarValue->punkVal = pfield;
pvarValue->punkVal->AddRef();
return S_OK;
}