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Diffstat (limited to 'Xamarin.Forms.Xaml/TypeConversionExtensions.cs')
| -rw-r--r-- | Xamarin.Forms.Xaml/TypeConversionExtensions.cs | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/Xamarin.Forms.Xaml/TypeConversionExtensions.cs b/Xamarin.Forms.Xaml/TypeConversionExtensions.cs new file mode 100644 index 00000000..a81ed11d --- /dev/null +++ b/Xamarin.Forms.Xaml/TypeConversionExtensions.cs @@ -0,0 +1,162 @@ +// +// InternalExtensions.cs +// +// Author: +// Stephane Delcroix <stephane@mi8.be> +// +// Copyright (c) 2013 Mobile Inception +// Copyright (c) 2014 Xamarin, Inc. +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in +// all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +// THE SOFTWARE. + +using System; +using System.Collections.Generic; +using System.Globalization; +using System.Linq; +using System.Reflection; + +namespace Xamarin.Forms.Xaml +{ + internal static class TypeConversionExtensions + { + internal static object ConvertTo(this object value, Type toType, Func<ParameterInfo> pinfoRetriever, + IServiceProvider serviceProvider) + { + Func<TypeConverter> getConverter = () => + { + ParameterInfo pInfo; + if (pinfoRetriever == null || (pInfo = pinfoRetriever()) == null) + return null; + + var converterTypeName = pInfo.CustomAttributes.GetTypeConverterTypeName(); + if (converterTypeName == null) + return null; + var convertertype = Type.GetType(converterTypeName); + return (TypeConverter)Activator.CreateInstance(convertertype); + }; + + return ConvertTo(value, toType, getConverter, serviceProvider); + } + + internal static object ConvertTo(this object value, Type toType, Func<MemberInfo> minfoRetriever, + IServiceProvider serviceProvider) + { + Func<object> getConverter = () => + { + MemberInfo memberInfo; + + var converterTypeName = toType.GetTypeInfo().CustomAttributes.GetTypeConverterTypeName(); + if (minfoRetriever != null && (memberInfo = minfoRetriever()) != null) + converterTypeName = memberInfo.CustomAttributes.GetTypeConverterTypeName() ?? converterTypeName; + if (converterTypeName == null) + return null; + + var convertertype = Type.GetType(converterTypeName); + return Activator.CreateInstance(convertertype); + }; + + return ConvertTo(value, toType, getConverter, serviceProvider); + } + + static string GetTypeConverterTypeName(this IEnumerable<CustomAttributeData> attributes) + { + var converterAttribute = + attributes.FirstOrDefault(cad => TypeConverterAttribute.TypeConvertersType.Contains(cad.AttributeType.FullName)); + if (converterAttribute == null) + return null; + if (converterAttribute.ConstructorArguments[0].ArgumentType == typeof (string)) + return (string)converterAttribute.ConstructorArguments[0].Value; + if (converterAttribute.ConstructorArguments[0].ArgumentType == typeof (Type)) + return ((Type)converterAttribute.ConstructorArguments[0].Value).AssemblyQualifiedName; + return null; + } + + //Don't change the name or the signature of this, it's used by XamlC + public static object ConvertTo(this object value, Type toType, Type convertertype, IServiceProvider serviceProvider) + { + if (convertertype == null) + return value.ConvertTo(toType, (Func<object>)null, serviceProvider); + Func<object> getConverter = () => Activator.CreateInstance(convertertype); + ; + return value.ConvertTo(toType, getConverter, serviceProvider); + } + + internal static object ConvertTo(this object value, Type toType, Func<object> getConverter, + IServiceProvider serviceProvider) + { + if (value == null) + return null; + + var str = value as string; + if (str != null) + { + //If there's a [TypeConverter], use it + object converter = getConverter?.Invoke(); + var xfTypeConverter = converter as TypeConverter; + var xfExtendedTypeConverter = xfTypeConverter as IExtendedTypeConverter; + if (xfExtendedTypeConverter != null) + return value = xfExtendedTypeConverter.ConvertFromInvariantString(str, serviceProvider); + if (xfTypeConverter != null) + return value = xfTypeConverter.ConvertFromInvariantString(str); + var converterType = converter?.GetType(); + if (converterType != null) + { + var convertFromStringInvariant = converterType.GetRuntimeMethod("ConvertFromInvariantString", + new[] { typeof (string) }); + if (convertFromStringInvariant != null) + return value = convertFromStringInvariant.Invoke(converter, new object[] { str }); + } + + //If the type is nullable, as the value is not null, it's safe to assume we want the built-in conversion + if (toType.GetTypeInfo().IsGenericType && toType.GetGenericTypeDefinition() == typeof (Nullable<>)) + toType = Nullable.GetUnderlyingType(toType); + + //Obvious Built-in conversions + if (toType.GetTypeInfo().IsEnum) + return Enum.Parse(toType, str); + //TODO supports Int16, 64, Byte, Char, ... + if (toType == typeof (Int32)) + return Int32.Parse(str, CultureInfo.InvariantCulture); + if (toType == typeof (float)) + return Single.Parse(str, CultureInfo.InvariantCulture); + if (toType == typeof (double)) + return Double.Parse(str, CultureInfo.InvariantCulture); + if (toType == typeof (bool)) + return Boolean.Parse(str); + if (toType == typeof (TimeSpan)) + return TimeSpan.Parse(str, CultureInfo.InvariantCulture); + if (toType == typeof (DateTime)) + return DateTime.Parse(str, CultureInfo.InvariantCulture); + if (toType == typeof (string) && str.StartsWith("{}", StringComparison.Ordinal)) + return str.Substring(2); + if (toType == typeof (string)) + return value; + } + + //if there's an implicit conversion, convert + if (value != null) + { + var cast = value.GetType().GetRuntimeMethod("op_Implicit", new[] { value.GetType() }); + if (cast != null && cast.ReturnType == toType) + value = cast.Invoke(null, new[] { value }); + } + return value; + } + } +}
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