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// Copyright (c) Microsoft Corporation. All rights reserved. See License.txt in the project root for license information.
using System.Collections;
using System.ComponentModel;
using System.Globalization;
using System.Web.Mvc.Properties;
namespace System.Web.Mvc
{
[Serializable]
public class ValueProviderResult
{
private static readonly CultureInfo _staticCulture = CultureInfo.InvariantCulture;
private CultureInfo _instanceCulture;
// default constructor so that subclassed types can set the properties themselves
protected ValueProviderResult()
{
}
public ValueProviderResult(object rawValue, string attemptedValue, CultureInfo culture)
{
RawValue = rawValue;
AttemptedValue = attemptedValue;
Culture = culture;
}
public string AttemptedValue { get; protected set; }
public CultureInfo Culture
{
get
{
if (_instanceCulture == null)
{
_instanceCulture = _staticCulture;
}
return _instanceCulture;
}
protected set { _instanceCulture = value; }
}
public object RawValue { get; protected set; }
private static object ConvertSimpleType(CultureInfo culture, object value, Type destinationType)
{
if (value == null || destinationType.IsInstanceOfType(value))
{
return value;
}
// if this is a user-input value but the user didn't type anything, return no value
string valueAsString = value as string;
if (valueAsString != null && valueAsString.Trim().Length == 0)
{
return null;
}
TypeConverter converter = TypeDescriptor.GetConverter(destinationType);
bool canConvertFrom = converter.CanConvertFrom(value.GetType());
if (!canConvertFrom)
{
converter = TypeDescriptor.GetConverter(value.GetType());
}
if (!(canConvertFrom || converter.CanConvertTo(destinationType)))
{
// EnumConverter cannot convert integer, so we verify manually
if (destinationType.IsEnum && value is int)
{
return Enum.ToObject(destinationType, (int)value);
}
// In case of a Nullable object, we try again with its underlying type.
Type underlyingType = Nullable.GetUnderlyingType(destinationType);
if (underlyingType != null)
{
return ConvertSimpleType(culture, value, underlyingType);
}
string message = String.Format(CultureInfo.CurrentCulture, MvcResources.ValueProviderResult_NoConverterExists,
value.GetType().FullName, destinationType.FullName);
throw new InvalidOperationException(message);
}
try
{
object convertedValue = (canConvertFrom)
? converter.ConvertFrom(null /* context */, culture, value)
: converter.ConvertTo(null /* context */, culture, value, destinationType);
return convertedValue;
}
catch (Exception ex)
{
string message = String.Format(CultureInfo.CurrentCulture, MvcResources.ValueProviderResult_ConversionThrew,
value.GetType().FullName, destinationType.FullName);
throw new InvalidOperationException(message, ex);
}
}
public object ConvertTo(Type type)
{
return ConvertTo(type, null /* culture */);
}
public virtual object ConvertTo(Type type, CultureInfo culture)
{
if (type == null)
{
throw new ArgumentNullException("type");
}
CultureInfo cultureToUse = culture ?? Culture;
return UnwrapPossibleArrayType(cultureToUse, RawValue, type);
}
private static object UnwrapPossibleArrayType(CultureInfo culture, object value, Type destinationType)
{
if (value == null || destinationType.IsInstanceOfType(value))
{
return value;
}
// array conversion results in four cases, as below
Array valueAsArray = value as Array;
if (destinationType.IsArray)
{
Type destinationElementType = destinationType.GetElementType();
if (valueAsArray != null)
{
// case 1: both destination + source type are arrays, so convert each element
IList converted = Array.CreateInstance(destinationElementType, valueAsArray.Length);
for (int i = 0; i < valueAsArray.Length; i++)
{
converted[i] = ConvertSimpleType(culture, valueAsArray.GetValue(i), destinationElementType);
}
return converted;
}
else
{
// case 2: destination type is array but source is single element, so wrap element in array + convert
object element = ConvertSimpleType(culture, value, destinationElementType);
IList converted = Array.CreateInstance(destinationElementType, 1);
converted[0] = element;
return converted;
}
}
else if (valueAsArray != null)
{
// case 3: destination type is single element but source is array, so extract first element + convert
if (valueAsArray.Length > 0)
{
value = valueAsArray.GetValue(0);
return ConvertSimpleType(culture, value, destinationType);
}
else
{
// case 3(a): source is empty array, so can't perform conversion
return null;
}
}
// case 4: both destination + source type are single elements, so convert
return ConvertSimpleType(culture, value, destinationType);
}
}
}
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