DocSpace-buildtools/web/ASC.Web.Core/Helpers/ResourceEnumConverter.cs
2019-06-07 11:59:07 +03:00

316 lines
14 KiB
C#

/*
*
* (c) Copyright Ascensio System Limited 2010-2018
*
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*
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*
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*/
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Globalization;
namespace ASC.Web.Core.Helpers
{
/// <summary>
/// Defines a type converter for enum values that converts enum values to
/// and from string representations using resources
/// </summary>
/// <remarks>
/// This class makes localization of display values for enums in a project easy. Simply
/// derive a class from this class and pass the ResourceManagerin the constructor.
///
/// Then define the enum values in the resource editor. The names of
/// the resources are simply the enum value prefixed by the enum type name with an
/// underscore separator eg MyEnum_MyValue. You can then use the TypeConverter attribute
/// to make the LocalizedEnumConverter the default TypeConverter for the enums in your
/// project.
/// </remarks>
public class ResourceEnumConverter : System.ComponentModel.EnumConverter
{
private class LookupTable : Dictionary<string, object> { }
private Dictionary<CultureInfo, LookupTable> _lookupTables = new Dictionary<CultureInfo, LookupTable>();
private System.Resources.ResourceManager _resourceManager;
private bool _isFlagEnum = false;
private Array _flagValues;
/// <summary>
/// Get the lookup table for the given culture (creating if necessary)
/// </summary>
/// <param name="culture"></param>
/// <returns></returns>
private LookupTable GetLookupTable(CultureInfo culture)
{
LookupTable result = null;
if (culture == null)
culture = CultureInfo.CurrentCulture;
if (!_lookupTables.TryGetValue(culture, out result))
{
result = new LookupTable();
foreach (object value in GetStandardValues())
{
string text = GetValueText(culture, value);
if (text != null)
{
result.Add(text, value);
}
}
_lookupTables.Add(culture, result);
}
return result;
}
/// <summary>
/// Return the text to display for a simple value in the given culture
/// </summary>
/// <param name="culture">The culture to get the text for</param>
/// <param name="value">The enum value to get the text for</param>
/// <returns>The localized text</returns>
private string GetValueText(CultureInfo culture, object value)
{
Type type = value.GetType();
string resourceName = string.Format("{0}_{1}", type.Name, value.ToString());
string result = _resourceManager.GetString(resourceName, culture);
if (result == null)
result = resourceName;
return result;
}
/// <summary>
/// Return true if the given value is can be represented using a single bit
/// </summary>
/// <param name="value"></param>
/// <returns></returns>
private bool IsSingleBitValue(ulong value)
{
switch (value)
{
case 0:
return false;
case 1:
return true;
}
return ((value & (value - 1)) == 0);
}
/// <summary>
/// Return the text to display for a flag value in the given culture
/// </summary>
/// <param name="culture">The culture to get the text for</param>
/// <param name="value">The flag enum value to get the text for</param>
/// <returns>The localized text</returns>
private string GetFlagValueText(CultureInfo culture, object value)
{
// if there is a standard value then use it
//
if (Enum.IsDefined(value.GetType(), value))
{
return GetValueText(culture, value);
}
// otherwise find the combination of flag bit values
// that makes up the value
//
ulong lValue = Convert.ToUInt32(value);
string result = null;
foreach (object flagValue in _flagValues)
{
ulong lFlagValue = Convert.ToUInt32(flagValue);
if (IsSingleBitValue(lFlagValue))
{
if ((lFlagValue & lValue) == lFlagValue)
{
string valueText = GetValueText(culture, flagValue);
if (result == null)
{
result = valueText;
}
else
{
result = string.Format("{0}, {1}", result, valueText);
}
}
}
}
return result;
}
/// <summary>
/// Return the Enum value for a simple (non-flagged enum)
/// </summary>
/// <param name="culture">The culture to convert using</param>
/// <param name="text">The text to convert</param>
/// <returns>The enum value</returns>
private object GetValue(CultureInfo culture, string text)
{
LookupTable lookupTable = GetLookupTable(culture);
object result = null;
lookupTable.TryGetValue(text, out result);
return result;
}
/// <summary>
/// Return the Enum value for a flagged enum
/// </summary>
/// <param name="culture">The culture to convert using</param>
/// <param name="text">The text to convert</param>
/// <returns>The enum value</returns>
private object GetFlagValue(CultureInfo culture, string text)
{
LookupTable lookupTable = GetLookupTable(culture);
string[] textValues = text.Split(',');
ulong result = 0;
foreach (string textValue in textValues)
{
object value = null;
string trimmedTextValue = textValue.Trim();
if (!lookupTable.TryGetValue(trimmedTextValue, out value))
{
return null;
}
result |= Convert.ToUInt32(value);
}
return Enum.ToObject(EnumType, result);
}
/// <summary>
/// Create a new instance of the converter using translations from the given resource manager
/// </summary>
/// <param name="type"></param>
/// <param name="resourceManager"></param>
public ResourceEnumConverter(Type type, System.Resources.ResourceManager resourceManager)
: base(type)
{
_resourceManager = resourceManager;
object[] flagAttributes = type.GetCustomAttributes(typeof(FlagsAttribute), true);
_isFlagEnum = flagAttributes.Length > 0;
if (_isFlagEnum)
{
_flagValues = Enum.GetValues(type);
}
}
/// <summary>
/// Convert string values to enum values
/// </summary>
/// <param name="context"></param>
/// <param name="culture"></param>
/// <param name="value"></param>
/// <returns></returns>
public override object ConvertFrom(System.ComponentModel.ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value)
{
if (value is string)
{
object result = (_isFlagEnum) ?
GetFlagValue(culture, (string)value): GetValue(culture, (string)value);
if (result == null)
{
result = base.ConvertFrom(context, culture, value);
}
return result;
}
else
{
return base.ConvertFrom(context, culture, value);
}
}
/// <summary>
/// Convert the enum value to a string
/// </summary>
/// <param name="context"></param>
/// <param name="culture"></param>
/// <param name="value"></param>
/// <param name="destinationType"></param>
/// <returns></returns>
public override object ConvertTo(System.ComponentModel.ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)
{
if (value != null && destinationType == typeof(string))
{
object result = (_isFlagEnum) ?
GetFlagValueText(culture, value) : GetValueText(culture, value);
return result;
}
else
{
return base.ConvertTo(context, culture, value, destinationType);
}
}
/// <summary>
/// Convert the given enum value to string using the registered type converter
/// </summary>
/// <param name="value">The enum value to convert to string</param>
/// <returns>The localized string value for the enum</returns>
static public string ConvertToString(Enum value)
{
TypeConverter converter = TypeDescriptor.GetConverter(value.GetType());
return converter.ConvertToString(value);
}
/// <summary>
/// Return a list of the enum values and their associated display text for the given enum type
/// </summary>
/// <param name="enumType">The enum type to get the values for</param>
/// <param name="culture">The culture to get the text for</param>
/// <returns>
/// A list of KeyValuePairs where the key is the enum value and the value is the text to display
/// </returns>
/// <remarks>
/// This method can be used to provide localized binding to enums in ASP.NET applications. Unlike
/// windows forms the standard ASP.NET controls do not use TypeConverters to convert from enum values
/// to the displayed text. You can bind an ASP.NET control to the list returned by this method by setting
/// the DataValueField to "Key" and theDataTextField to "Value".
/// </remarks>
static public List<KeyValuePair<Enum, string>> GetValues(Type enumType, CultureInfo culture)
{
List<KeyValuePair<Enum, string>> result = new List<KeyValuePair<Enum, string>>();
TypeConverter converter = TypeDescriptor.GetConverter(enumType);
foreach (Enum value in Enum.GetValues(enumType))
{
KeyValuePair<Enum, string> pair = new KeyValuePair<Enum, string>(value, converter.ConvertToString(null, culture, value));
result.Add(pair);
}
return result;
}
/// <summary>
/// Return a list of the enum values and their associated display text for the given enum type in the current UI Culture
/// </summary>
/// <param name="enumType">The enum type to get the values for</param>
/// <returns>
/// A list of KeyValuePairs where the key is the enum value and the value is the text to display
/// </returns>
/// <remarks>
/// This method can be used to provide localized binding to enums in ASP.NET applications. Unlike
/// windows forms the standard ASP.NET controls do not use TypeConverters to convert from enum values
/// to the displayed text. You can bind an ASP.NET control to the list returned by this method by setting
/// the DataValueField to "Key" and theDataTextField to "Value".
/// </remarks>
static public List<KeyValuePair<Enum, string>> GetValues(Type enumType)
{
return GetValues(enumType, CultureInfo.CurrentUICulture);
}
}
}