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//------------------------------------------------------------------------------
// <copyright file="PropertyConverter.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//------------------------------------------------------------------------------
namespace System.Web.UI {
using System;
using System.ComponentModel;
using System.Globalization;
using System.Reflection;
using System.Runtime.Serialization.Formatters;
/// <internalonly/>
/// <devdoc>
/// </devdoc>
public static class PropertyConverter {
private static readonly Type[] s_parseMethodTypes = new Type[] { typeof(string) };
private static readonly Type[] s_parseMethodTypesWithSOP = new Type[] { typeof(string), typeof(IServiceProvider) };
/*
* Contains helpers to convert properties from strings to their types and vice versa.
*/
/*
* Converts a persisted enumeration value into its numeric value.
* Hyphen characters in the persisted format are converted to underscores.
*/
/// <devdoc>
/// </devdoc>
public static object EnumFromString(Type enumType, string value) {
try {
return Enum.Parse(enumType, value, true);
}
catch {
return null;
}
}
/*
* Converts a numeric enumerated value into its persisted form, which is the
* code name with underscores replaced by hyphens.
*/
/// <devdoc>
/// </devdoc>
public static string EnumToString(Type enumType, object enumValue) {
string value = Enum.Format(enumType, enumValue, "G");
//
return value.Replace('_','-');
}
/*
* Converts the persisted string into an object using the object's
* FromString method.
*/
/// <devdoc>
/// </devdoc>
public static object ObjectFromString(Type objType, MemberInfo propertyInfo, string value) {
if (value == null)
return null;
// Blank valued bools don't map with FromString. Return null to allow
// caller to interpret.
if (objType.Equals(typeof(bool)) && value.Length == 0) {
return null;
}
bool useParseMethod = true;
object ret = null;
try {
if (objType.IsEnum) {
useParseMethod = false;
ret = EnumFromString(objType, value);
}
else if (objType.Equals(typeof(string))) {
useParseMethod = false;
ret = value;
}
else {
PropertyDescriptor pd = null;
if (propertyInfo != null) {
pd = TypeDescriptor.GetProperties(propertyInfo.ReflectedType)[propertyInfo.Name];
}
if (pd != null) {
TypeConverter converter = pd.Converter;
if (converter != null && converter.CanConvertFrom(typeof(string))) {
useParseMethod = false;
ret = converter.ConvertFromInvariantString(value);
}
}
}
}
catch {
}
if (useParseMethod) {
// resort to Parse static method on the type
// First try Parse(string, IServiceProvider);
MethodInfo methodInfo = objType.GetMethod("Parse", s_parseMethodTypesWithSOP);
if (methodInfo != null) {
object[] parameters = new object[2];
parameters[0] = value;
parameters[1] = CultureInfo.InvariantCulture;
try {
ret = Util.InvokeMethod(methodInfo, null, parameters);
}
catch {
}
}
else {
// Try the simpler: Parse(string);
methodInfo = objType.GetMethod("Parse", s_parseMethodTypes);
if (methodInfo != null) {
object[] parameters = new object[1];
parameters[0] = value;
try {
ret = Util.InvokeMethod(methodInfo, null, parameters);
}
catch {
}
}
}
}
if (ret == null) {
// Unhandled... throw an exception, so user sees an error at parse time
// Note that we don't propagate inner exceptions here, since they usually
// do not give any information about where the bad value existed on
// the object being initialized, whereas, our exception gives that
// information.
throw new HttpException(SR.GetString(SR.Type_not_creatable_from_string,
objType.FullName, value, propertyInfo.Name));
}
return ret;
}
}
}
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