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Diffstat (limited to 'Xamarin.Forms.Core/BindableProperty.cs')
| -rw-r--r-- | Xamarin.Forms.Core/BindableProperty.cs | 331 |
1 files changed, 331 insertions, 0 deletions
diff --git a/Xamarin.Forms.Core/BindableProperty.cs b/Xamarin.Forms.Core/BindableProperty.cs new file mode 100644 index 00000000..f95d38ab --- /dev/null +++ b/Xamarin.Forms.Core/BindableProperty.cs @@ -0,0 +1,331 @@ +using System; +using System.Collections.Generic; +using System.Diagnostics; +using System.Linq.Expressions; +using System.Reflection; + +namespace Xamarin.Forms +{ + [DebuggerDisplay("{PropertyName}")] + [TypeConverter(typeof(BindablePropertyConverter))] + public sealed class BindableProperty + { + public delegate void BindingPropertyChangedDelegate(BindableObject bindable, object oldValue, object newValue); + + public delegate void BindingPropertyChangedDelegate<in TPropertyType>(BindableObject bindable, TPropertyType oldValue, TPropertyType newValue); + + public delegate void BindingPropertyChangingDelegate(BindableObject bindable, object oldValue, object newValue); + + public delegate void BindingPropertyChangingDelegate<in TPropertyType>(BindableObject bindable, TPropertyType oldValue, TPropertyType newValue); + + public delegate object CoerceValueDelegate(BindableObject bindable, object value); + + public delegate TPropertyType CoerceValueDelegate<TPropertyType>(BindableObject bindable, TPropertyType value); + + public delegate object CreateDefaultValueDelegate(BindableObject bindable); + + public delegate TPropertyType CreateDefaultValueDelegate<in TDeclarer, out TPropertyType>(TDeclarer bindable); + + public delegate bool ValidateValueDelegate(BindableObject bindable, object value); + + public delegate bool ValidateValueDelegate<in TPropertyType>(BindableObject bindable, TPropertyType value); + + // more or less the encoding of this, without the need to reflect + // http://msdn.microsoft.com/en-us/library/y5b434w4.aspx + static readonly Dictionary<Type, Type[]> SimpleConvertTypes = new Dictionary<Type, Type[]> + { + { typeof(sbyte), new[] { typeof(string), typeof(short), typeof(int), typeof(long), typeof(float), typeof(double), typeof(decimal) } }, + { typeof(byte), new[] { typeof(string), typeof(short), typeof(ushort), typeof(int), typeof(uint), typeof(ulong), typeof(float), typeof(double), typeof(decimal) } }, + { typeof(short), new[] { typeof(string), typeof(int), typeof(long), typeof(float), typeof(double), typeof(decimal) } }, + { typeof(ushort), new[] { typeof(string), typeof(int), typeof(uint), typeof(long), typeof(ulong), typeof(float), typeof(double), typeof(decimal) } }, + { typeof(int), new[] { typeof(string), typeof(long), typeof(float), typeof(double), typeof(decimal) } }, + { typeof(uint), new[] { typeof(string), typeof(long), typeof(ulong), typeof(float), typeof(double), typeof(decimal) } }, + { typeof(long), new[] { typeof(string), typeof(float), typeof(double), typeof(decimal) } }, + { typeof(char), new[] { typeof(string), typeof(ushort), typeof(int), typeof(uint), typeof(long), typeof(ulong), typeof(float), typeof(double), typeof(decimal) } }, + { typeof(float), new[] { typeof(string), typeof(double) } }, + { typeof(ulong), new[] { typeof(string), typeof(float), typeof(double), typeof(decimal) } } + }; + + BindableProperty(string propertyName, Type returnType, Type declaringType, object defaultValue, BindingMode defaultBindingMode = BindingMode.OneWay, + ValidateValueDelegate validateValue = null, BindingPropertyChangedDelegate propertyChanged = null, BindingPropertyChangingDelegate propertyChanging = null, + CoerceValueDelegate coerceValue = null, BindablePropertyBindingChanging bindingChanging = null, bool isReadOnly = false, CreateDefaultValueDelegate defaultValueCreator = null) + { + if (propertyName == null) + throw new ArgumentNullException("propertyName"); + if (ReferenceEquals(returnType, null)) + throw new ArgumentNullException("returnType"); + if (ReferenceEquals(declaringType, null)) + throw new ArgumentNullException("declaringType"); + + // don't use Enum.IsDefined as its redonkulously expensive for what it does + if (defaultBindingMode != BindingMode.Default && defaultBindingMode != BindingMode.OneWay && defaultBindingMode != BindingMode.OneWayToSource && defaultBindingMode != BindingMode.TwoWay) + throw new ArgumentException("Not a valid type of BindingMode", "defaultBindingMode"); + if (defaultValue == null && Nullable.GetUnderlyingType(returnType) == null && returnType.GetTypeInfo().IsValueType) + throw new ArgumentException("Not a valid default value", "defaultValue"); + if (defaultValue != null && !returnType.IsInstanceOfType(defaultValue)) + throw new ArgumentException("Default value did not match return type", "defaultValue"); + if (defaultBindingMode == BindingMode.Default) + defaultBindingMode = BindingMode.OneWay; + + PropertyName = propertyName; + ReturnType = returnType; + ReturnTypeInfo = returnType.GetTypeInfo(); + DeclaringType = declaringType; + DefaultValue = defaultValue; + DefaultBindingMode = defaultBindingMode; + PropertyChanged = propertyChanged; + PropertyChanging = propertyChanging; + ValidateValue = validateValue; + CoerceValue = coerceValue; + BindingChanging = bindingChanging; + IsReadOnly = isReadOnly; + DefaultValueCreator = defaultValueCreator; + } + + public Type DeclaringType { get; private set; } + + public BindingMode DefaultBindingMode { get; private set; } + + public object DefaultValue { get; } + + public bool IsReadOnly { get; private set; } + + public string PropertyName { get; } + + public Type ReturnType { get; } + + internal BindablePropertyBindingChanging BindingChanging { get; private set; } + + internal CoerceValueDelegate CoerceValue { get; private set; } + + internal CreateDefaultValueDelegate DefaultValueCreator { get; } + + internal BindingPropertyChangedDelegate PropertyChanged { get; private set; } + + internal BindingPropertyChangingDelegate PropertyChanging { get; private set; } + + internal TypeInfo ReturnTypeInfo { get; } + + internal ValidateValueDelegate ValidateValue { get; private set; } + + [Obsolete("Generic versions of Create () are no longer supported and deprecated. They will be removed soon.")] + public static BindableProperty Create<TDeclarer, TPropertyType>(Expression<Func<TDeclarer, TPropertyType>> getter, TPropertyType defaultValue, BindingMode defaultBindingMode = BindingMode.OneWay, + ValidateValueDelegate<TPropertyType> validateValue = null, BindingPropertyChangedDelegate<TPropertyType> propertyChanged = null, + BindingPropertyChangingDelegate<TPropertyType> propertyChanging = null, CoerceValueDelegate<TPropertyType> coerceValue = null, + CreateDefaultValueDelegate<TDeclarer, TPropertyType> defaultValueCreator = null) where TDeclarer : BindableObject + { + return Create(getter, defaultValue, defaultBindingMode, validateValue, propertyChanged, propertyChanging, coerceValue, null, defaultValueCreator: defaultValueCreator); + } + + public static BindableProperty Create(string propertyName, Type returnType, Type declaringType, object defaultValue = null, BindingMode defaultBindingMode = BindingMode.OneWay, + ValidateValueDelegate validateValue = null, BindingPropertyChangedDelegate propertyChanged = null, BindingPropertyChangingDelegate propertyChanging = null, + CoerceValueDelegate coerceValue = null, CreateDefaultValueDelegate defaultValueCreator = null) + { + return new BindableProperty(propertyName, returnType, declaringType, defaultValue, defaultBindingMode, validateValue, propertyChanged, propertyChanging, coerceValue, + defaultValueCreator: defaultValueCreator); + } + + [Obsolete("Generic versions of Create () are no longer supported and deprecated. They will be removed soon.")] + public static BindableProperty CreateAttached<TDeclarer, TPropertyType>(Expression<Func<BindableObject, TPropertyType>> staticgetter, TPropertyType defaultValue, + BindingMode defaultBindingMode = BindingMode.OneWay, ValidateValueDelegate<TPropertyType> validateValue = null, BindingPropertyChangedDelegate<TPropertyType> propertyChanged = null, + BindingPropertyChangingDelegate<TPropertyType> propertyChanging = null, CoerceValueDelegate<TPropertyType> coerceValue = null, + CreateDefaultValueDelegate<BindableObject, TPropertyType> defaultValueCreator = null) + { + return CreateAttached<TDeclarer, TPropertyType>(staticgetter, defaultValue, defaultBindingMode, validateValue, propertyChanged, propertyChanging, coerceValue, null, + defaultValueCreator: defaultValueCreator); + } + + public static BindableProperty CreateAttached(string propertyName, Type returnType, Type declaringType, object defaultValue, BindingMode defaultBindingMode = BindingMode.OneWay, + ValidateValueDelegate validateValue = null, BindingPropertyChangedDelegate propertyChanged = null, BindingPropertyChangingDelegate propertyChanging = null, + CoerceValueDelegate coerceValue = null, CreateDefaultValueDelegate defaultValueCreator = null) + { + return CreateAttached(propertyName, returnType, declaringType, defaultValue, defaultBindingMode, validateValue, propertyChanged, propertyChanging, coerceValue, null, false, defaultValueCreator); + } + + [Obsolete("Generic versions of Create () are no longer supported and deprecated. They will be removed soon.")] + public static BindablePropertyKey CreateAttachedReadOnly<TDeclarer, TPropertyType>(Expression<Func<BindableObject, TPropertyType>> staticgetter, TPropertyType defaultValue, + BindingMode defaultBindingMode = BindingMode.OneWayToSource, ValidateValueDelegate<TPropertyType> validateValue = null, + BindingPropertyChangedDelegate<TPropertyType> propertyChanged = null, BindingPropertyChangingDelegate<TPropertyType> propertyChanging = null, + CoerceValueDelegate<TPropertyType> coerceValue = null, CreateDefaultValueDelegate<BindableObject, TPropertyType> defaultValueCreator = null) + + { + return + new BindablePropertyKey(CreateAttached<TDeclarer, TPropertyType>(staticgetter, defaultValue, defaultBindingMode, validateValue, propertyChanged, propertyChanging, coerceValue, null, true, + defaultValueCreator)); + } + + public static BindablePropertyKey CreateAttachedReadOnly(string propertyName, Type returnType, Type declaringType, object defaultValue, BindingMode defaultBindingMode = BindingMode.OneWayToSource, + ValidateValueDelegate validateValue = null, BindingPropertyChangedDelegate propertyChanged = null, BindingPropertyChangingDelegate propertyChanging = null, + CoerceValueDelegate coerceValue = null, CreateDefaultValueDelegate defaultValueCreator = null) + { + return + new BindablePropertyKey(CreateAttached(propertyName, returnType, declaringType, defaultValue, defaultBindingMode, validateValue, propertyChanged, propertyChanging, coerceValue, null, true, + defaultValueCreator)); + } + + [Obsolete("Generic versions of Create () are no longer supported and deprecated. They will be removed soon.")] + public static BindablePropertyKey CreateReadOnly<TDeclarer, TPropertyType>(Expression<Func<TDeclarer, TPropertyType>> getter, TPropertyType defaultValue, + BindingMode defaultBindingMode = BindingMode.OneWayToSource, ValidateValueDelegate<TPropertyType> validateValue = null, + BindingPropertyChangedDelegate<TPropertyType> propertyChanged = null, BindingPropertyChangingDelegate<TPropertyType> propertyChanging = null, + CoerceValueDelegate<TPropertyType> coerceValue = null, CreateDefaultValueDelegate<TDeclarer, TPropertyType> defaultValueCreator = null) where TDeclarer : BindableObject + { + return new BindablePropertyKey(Create(getter, defaultValue, defaultBindingMode, validateValue, propertyChanged, propertyChanging, coerceValue, null, true, defaultValueCreator)); + } + + public static BindablePropertyKey CreateReadOnly(string propertyName, Type returnType, Type declaringType, object defaultValue, BindingMode defaultBindingMode = BindingMode.OneWayToSource, + ValidateValueDelegate validateValue = null, BindingPropertyChangedDelegate propertyChanged = null, BindingPropertyChangingDelegate propertyChanging = null, + CoerceValueDelegate coerceValue = null, CreateDefaultValueDelegate defaultValueCreator = null) + { + return + new BindablePropertyKey(new BindableProperty(propertyName, returnType, declaringType, defaultValue, defaultBindingMode, validateValue, propertyChanged, propertyChanging, coerceValue, + isReadOnly: true, defaultValueCreator: defaultValueCreator)); + } + + [Obsolete("Generic versions of Create () are no longer supported and deprecated. They will be removed soon.")] + internal static BindableProperty Create<TDeclarer, TPropertyType>(Expression<Func<TDeclarer, TPropertyType>> getter, TPropertyType defaultValue, BindingMode defaultBindingMode, + ValidateValueDelegate<TPropertyType> validateValue, BindingPropertyChangedDelegate<TPropertyType> propertyChanged, BindingPropertyChangingDelegate<TPropertyType> propertyChanging, + CoerceValueDelegate<TPropertyType> coerceValue, BindablePropertyBindingChanging bindingChanging, bool isReadOnly = false, + CreateDefaultValueDelegate<TDeclarer, TPropertyType> defaultValueCreator = null) where TDeclarer : BindableObject + { + if (getter == null) + throw new ArgumentNullException("getter"); + + Expression expr = getter.Body; + + var unary = expr as UnaryExpression; + if (unary != null) + expr = unary.Operand; + + var member = expr as MemberExpression; + if (member == null) + throw new ArgumentException("getter must be a MemberExpression", "getter"); + + var property = (PropertyInfo)member.Member; + + ValidateValueDelegate untypedValidateValue = null; + BindingPropertyChangedDelegate untypedBindingPropertyChanged = null; + BindingPropertyChangingDelegate untypedBindingPropertyChanging = null; + CoerceValueDelegate untypedCoerceValue = null; + CreateDefaultValueDelegate untypedDefaultValueCreator = null; + if (validateValue != null) + untypedValidateValue = (bindable, value) => validateValue(bindable, (TPropertyType)value); + if (propertyChanged != null) + untypedBindingPropertyChanged = (bindable, oldValue, newValue) => propertyChanged(bindable, (TPropertyType)oldValue, (TPropertyType)newValue); + if (propertyChanging != null) + untypedBindingPropertyChanging = (bindable, oldValue, newValue) => propertyChanging(bindable, (TPropertyType)oldValue, (TPropertyType)newValue); + if (coerceValue != null) + untypedCoerceValue = (bindable, value) => coerceValue(bindable, (TPropertyType)value); + if (defaultValueCreator != null) + untypedDefaultValueCreator = o => defaultValueCreator((TDeclarer)o); + + return new BindableProperty(property.Name, property.PropertyType, typeof(TDeclarer), defaultValue, defaultBindingMode, untypedValidateValue, untypedBindingPropertyChanged, + untypedBindingPropertyChanging, untypedCoerceValue, bindingChanging, isReadOnly, untypedDefaultValueCreator); + } + + internal static BindableProperty Create(string propertyName, Type returnType, Type declaringType, object defaultValue, BindingMode defaultBindingMode, ValidateValueDelegate validateValue, + BindingPropertyChangedDelegate propertyChanged, BindingPropertyChangingDelegate propertyChanging, CoerceValueDelegate coerceValue, BindablePropertyBindingChanging bindingChanging, + CreateDefaultValueDelegate defaultValueCreator = null) + { + return new BindableProperty(propertyName, returnType, declaringType, defaultValue, defaultBindingMode, validateValue, propertyChanged, propertyChanging, coerceValue, bindingChanging, + defaultValueCreator: defaultValueCreator); + } + + [Obsolete("Generic versions of Create () are no longer supported and deprecated. They will be removed soon.")] + internal static BindableProperty CreateAttached<TDeclarer, TPropertyType>(Expression<Func<BindableObject, TPropertyType>> staticgetter, TPropertyType defaultValue, BindingMode defaultBindingMode, + ValidateValueDelegate<TPropertyType> validateValue, BindingPropertyChangedDelegate<TPropertyType> propertyChanged, BindingPropertyChangingDelegate<TPropertyType> propertyChanging, + CoerceValueDelegate<TPropertyType> coerceValue, BindablePropertyBindingChanging bindingChanging, bool isReadOnly = false, + CreateDefaultValueDelegate<BindableObject, TPropertyType> defaultValueCreator = null) + { + if (staticgetter == null) + throw new ArgumentNullException("staticgetter"); + + Expression expr = staticgetter.Body; + + var unary = expr as UnaryExpression; + if (unary != null) + expr = unary.Operand; + + var methodcall = expr as MethodCallExpression; + if (methodcall == null) + throw new ArgumentException("staticgetter must be a MethodCallExpression", "staticgetter"); + + MethodInfo method = methodcall.Method; + if (!method.Name.StartsWith("Get", StringComparison.Ordinal)) + throw new ArgumentException("staticgetter name must start with Get", "staticgetter"); + + string propertyname = method.Name.Substring(3); + + ValidateValueDelegate untypedValidateValue = null; + BindingPropertyChangedDelegate untypedBindingPropertyChanged = null; + BindingPropertyChangingDelegate untypedBindingPropertyChanging = null; + CoerceValueDelegate untypedCoerceValue = null; + CreateDefaultValueDelegate untypedDefaultValueCreator = null; + if (validateValue != null) + untypedValidateValue = (bindable, value) => validateValue(bindable, (TPropertyType)value); + if (propertyChanged != null) + untypedBindingPropertyChanged = (bindable, oldValue, newValue) => propertyChanged(bindable, (TPropertyType)oldValue, (TPropertyType)newValue); + if (propertyChanging != null) + untypedBindingPropertyChanging = (bindable, oldValue, newValue) => propertyChanging(bindable, (TPropertyType)oldValue, (TPropertyType)newValue); + if (coerceValue != null) + untypedCoerceValue = (bindable, value) => coerceValue(bindable, (TPropertyType)value); + if (defaultValueCreator != null) + untypedDefaultValueCreator = o => defaultValueCreator(o); + + return new BindableProperty(propertyname, method.ReturnType, typeof(TDeclarer), defaultValue, defaultBindingMode, untypedValidateValue, untypedBindingPropertyChanged, untypedBindingPropertyChanging, + untypedCoerceValue, bindingChanging, isReadOnly, untypedDefaultValueCreator); + } + + internal static BindableProperty CreateAttached(string propertyName, Type returnType, Type declaringType, object defaultValue, BindingMode defaultBindingMode, ValidateValueDelegate validateValue, + BindingPropertyChangedDelegate propertyChanged, BindingPropertyChangingDelegate propertyChanging, CoerceValueDelegate coerceValue, BindablePropertyBindingChanging bindingChanging, + bool isReadOnly, CreateDefaultValueDelegate defaultValueCreator = null) + { + return new BindableProperty(propertyName, returnType, declaringType, defaultValue, defaultBindingMode, validateValue, propertyChanged, propertyChanging, coerceValue, bindingChanging, isReadOnly, + defaultValueCreator); + } + + internal object GetDefaultValue(BindableObject bindable) + { + if (DefaultValueCreator != null) + return DefaultValueCreator(bindable); + + return DefaultValue; + } + + internal bool TryConvert(ref object value) + { + if (value == null) + { + return !ReturnTypeInfo.IsValueType || ReturnTypeInfo.IsGenericType && ReturnTypeInfo.GetGenericTypeDefinition() == typeof(Nullable<>); + } + + Type valueType = value.GetType(); + Type type = ReturnType; + + // Dont support arbitrary IConvertible by limiting which types can use this + Type[] convertableTo; + if (SimpleConvertTypes.TryGetValue(valueType, out convertableTo) && Array.IndexOf(convertableTo, type) != -1) + { + value = Convert.ChangeType(value, type); + } + else if (!ReturnTypeInfo.IsAssignableFrom(valueType.GetTypeInfo())) + { + // Is there an implicit cast operator ? + MethodInfo cast = type.GetRuntimeMethod("op_Implicit", new[] { valueType }); + if (cast != null && cast.ReturnType != type) + cast = null; + if (cast == null) + cast = valueType.GetRuntimeMethod("op_Implicit", new[] { valueType }); + if (cast != null && cast.ReturnType != type) + cast = null; + if (cast == null) + return false; + + value = cast.Invoke(null, new[] { value }); + } + + return true; + } + + internal delegate void BindablePropertyBindingChanging(BindableObject bindable, BindingBase oldValue, BindingBase newValue); + } +}
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