public static IValueProvider GetResource <T>(object value, object defaultValue,
Func <string, object> deserializer)
{
if (value == null)
{
return(new LiteralValue(defaultValue));
}
if (value is string expression)
{
var boundExpression = BoundExpression.Parse(expression);
switch (boundExpression.Resources.Count)
{
case 0 when deserializer != null:
return(new LiteralValue(deserializer(expression)));
case 1 when boundExpression.StringFormat == null:
return(new CoercedValueProvider <T>(boundExpression.Resources[0], defaultValue));
default:
throw new ArgumentException(
$"The expression '{expression}' is not a valid resource because it does not define a single value source.",
nameof(value));
}
}
if (value is T)
{
return(new LiteralValue(value));
}
throw new ArgumentException(
$"The provided value must be a bound resource or a literal value of type '{typeof(T).FullName}'.",
nameof(value));
}
public static Func <IResourceContext, IErrorStringProvider> GetErrorProvider(string message, string propertyKey)
{
var func = GetValueProvider(propertyKey);
var boundExpression = BoundExpression.Parse(message, new Dictionary <string, object>
{
["Value"] = func
});
if (boundExpression.IsPlainString)
{
var errorMessage = boundExpression.StringFormat;
return(context => new PlainErrorStringProvider(errorMessage));
}
if (boundExpression.Resources.Any(
res => res is DeferredProxyResource resource && resource.ProxyProvider == func))
{
var key = propertyKey;
return(context => new ValueErrorStringProvider(boundExpression.GetStringValue(context), GetValueProxy(context, key)));
}
return(context => new ErrorStringProvider(boundExpression.GetStringValue(context)));
}
public FormElement TryBuild(IFormProperty property, Func <string, object> deserializer)
{
var selectFrom = property.GetCustomAttribute <SelectFromAttribute>();
if (selectFrom == null)
{
return(null);
}
var type = property.PropertyType;
var field = new SelectionField(property.Name, property.PropertyType);
if (selectFrom.DisplayPath != null)
{
field.DisplayPath = BoundExpression.ParseSimplified(selectFrom.DisplayPath);
}
if (selectFrom.ValuePath != null)
{
field.ValuePath = BoundExpression.ParseSimplified(selectFrom.ValuePath);
}
if (selectFrom.ItemStringFormat != null)
{
field.ItemStringFormat = BoundExpression.ParseSimplified(selectFrom.ItemStringFormat);
}
field.SelectionType = Utilities.GetResource <SelectionType>(selectFrom.SelectionType, SelectionType.ComboBox, Deserializers.Enum <SelectionType>());
switch (selectFrom.ItemsSource)
{
case string expr:
var value = BoundExpression.Parse(expr);
if (!value.IsSingleResource)
{
throw new InvalidOperationException("ItemsSource must be a single resource reference.");
}
field.ItemsSource = value.Resources[0];
break;
case IEnumerable <object> enumerable:
field.ItemsSource = new LiteralValue(enumerable.ToList());
break;
case Type enumType:
if (!enumType.IsEnum)
{
throw new InvalidOperationException("A type argument for ItemsSource must be an enum.");
}
var values = Enum.GetValues(enumType);
var collection = new List <KeyValuePair <ValueType, IValueProvider> >();
foreach (Enum enumValue in values)
{
var enumName = enumValue.ToString();
var memInfo = enumType.GetMember(enumName);
var attributes = memInfo[0].GetCustomAttributes(typeof(EnumDisplayAttribute), false);
IValueProvider name;
if (attributes.Length > 0)
{
var attr = (EnumDisplayAttribute)attributes[0];
name = BoundExpression.ParseSimplified(attr.Name);
}
else
{
name = new LiteralValue(enumName.Humanize());
}
collection.Add(new KeyValuePair <ValueType, IValueProvider>(enumValue, name));
}
field.ItemsSource = new EnumerableStringValueProvider(collection);
field.DisplayPath = new LiteralValue(nameof(StringProxy.Value));
field.ValuePath = new LiteralValue(type == typeof(string)
? nameof(StringProxy.Value)
: nameof(StringProxy.Key));
break;
}
return(field);
}
private FormDefinition BuildDefinition(Type type)
{
// Only classes are allowed.
// Primitives should be retrieved from prebuilt definitions.
if (!type.IsClass || typeof(MulticastDelegate).IsAssignableFrom(type.BaseType))
{
return(null);
}
var formDefinition = new FormDefinition(type);
var mode = DefaultFields.AllExcludingReadonly;
var grid = new[] { 1d };
var beforeFormContent = new List <AttrElementTuple>();
var afterFormContent = new List <AttrElementTuple>();
foreach (var attribute in type.GetCustomAttributes())
{
switch (attribute)
{
case ResourceAttribute resource:
formDefinition.Resources.Add(resource.Name, resource.Value is string expr
? (IValueProvider)BoundExpression.Parse(expr)
: new LiteralValue(resource.Value));
break;
case FormAttribute form:
mode = form.Mode;
grid = form.Grid;
if (grid == null || grid.Length < 1)
{
grid = new[] { 1d };
}
break;
case FormContentAttribute contentAttribute:
if (contentAttribute.Placement == Placement.After)
{
afterFormContent.Add(new AttrElementTuple(contentAttribute, contentAttribute.GetElement()));
}
else if (contentAttribute.Placement == Placement.Before)
{
beforeFormContent.Add(new AttrElementTuple(contentAttribute,
contentAttribute.GetElement()));
}
break;
case MetaAttribute meta:
if (!string.IsNullOrEmpty(meta.Name))
{
formDefinition.Metadata[meta.Name] = meta.Value;
}
break;
}
}
beforeFormContent.Sort((a, b) => a.Attr.Position.CompareTo(b.Attr.Position));
afterFormContent.Sort((a, b) => a.Attr.Position.CompareTo(b.Attr.Position));
var gridLength = grid.Length;
// Pass one - get list of valid properties.
var properties = Utilities
.GetProperties(type, mode)
.Select(p => new PropertyInfoWrapper(p))
.ToArray();
// Pass two - build form elements.
var elements = new List <ElementWrapper>();
foreach (var property in properties)
{
var deserializer = TryGetDeserializer(property.PropertyType);
// Query property builders.
var element = Build(property, deserializer);
if (element == null)
{
// Unhandled properties are ignored.
continue;
}
// Pass three - initialize elements.
foreach (var initializer in FieldInitializers)
{
initializer.Initialize(element, property, deserializer);
}
var wrapper = new ElementWrapper(element, property);
// Set layout.
var attr = property.GetCustomAttribute <FieldAttribute>();
if (attr != null)
{
wrapper.Position = attr.Position;
wrapper.Row = attr.Row;
wrapper.Column = attr.Column;
wrapper.ColumnSpan = attr.ColumnSpan;
}
elements.Add(wrapper);
}
// Pass four - order elements.
elements = elements.OrderBy(element => element.Position).ToList();
// Pass five - group rows and calculate layout.
var layout = PerformLayout(grid, elements);
// Pass six - add attached elements.
var rows = new List <FormRow>();
// Before form.
rows.AddRange(CreateRows(beforeFormContent, gridLength));
foreach (var row in layout)
{
var before = new List <AttrElementTuple>();
var after = new List <AttrElementTuple>();
foreach (var element in row.Elements)
{
var property = element.Property;
foreach (var attr in property.GetCustomAttributes <FormContentAttribute>())
{
if (attr.Placement == Placement.Before)
{
before.Add(new AttrElementTuple(attr, attr.GetElement()));
}
else if (attr.Placement == Placement.After)
{
after.Add(new AttrElementTuple(attr, attr.GetElement()));
}
}
}
before.Sort((a, b) => a.Attr.Position.CompareTo(b.Attr.Position));
after.Sort((a, b) => a.Attr.Position.CompareTo(b.Attr.Position));
// Before element.
rows.AddRange(CreateRows(before, gridLength));
// Field row.
var formRow = new FormRow();
formRow.Elements.AddRange(
row.Elements.Select(w =>
{
var inlineElements = w.Property
.GetCustomAttributes <FormContentAttribute>()
.Where(attr => attr.Placement == Placement.Inline)
.Select(attr => new AttrElementTuple(attr, attr.GetElement()))
.OrderBy(tuple => tuple.Attr.Position)
.ToList();
w.Element.LinePosition = (Position)(-1);
if (inlineElements.Count != 0)
{
return(new FormElementContainer(w.Column, w.ColumnSpan,
inlineElements
.Select(t => t.Element)
.Concat(new[] { w.Element })
.ToList()));
}
return(new FormElementContainer(w.Column, w.ColumnSpan, w.Element));
}));
rows.Add(formRow);
// After element.
rows.AddRange(CreateRows(after, gridLength));
}
// After form.
rows.AddRange(CreateRows(afterFormContent, gridLength));
// Wrap up everything.
formDefinition.Grid = grid;
formDefinition.FormRows = rows;
formDefinition.Freeze();
foreach (var element in formDefinition.FormRows.SelectMany(r => r.Elements).SelectMany(c => c.Elements))
{
element.Freeze();
}
return(formDefinition);
}
private static IValidatorProvider CreateValidator(Type modelType, string propertyKey, ValueAttribute attribute, Func <string, object> deserializer)
{
Func <IResourceContext, IProxy> argumentProvider;
var argument = attribute.Argument;
if (argument is string expression)
{
var boundExpression = BoundExpression.Parse(expression);
if (boundExpression.IsPlainString)
{
var literal = new PlainObject(deserializer != null
? deserializer(boundExpression.StringFormat)
: boundExpression.StringFormat);
argumentProvider = context => literal;
}
else
{
var getString = boundExpression.StringFormat != null;
var action = attribute.ArgumentUpdatedAction;
var notify = action == ValidationAction.ClearErrors || action == ValidationAction.ValidateField;
argumentProvider = context =>
{
var value = getString
? (IProxy)boundExpression.GetStringValue(context)
: boundExpression.GetValue(context);
if (notify)
{
value.ValueChanged = () =>
{
object model;
try
{
model = context.GetModelInstance();
}
catch
{
// Something went wrong so it's best to
// disable the feature entirely.
value.ValueChanged = null;
return;
}
if (model is ExpandoObject && modelType == null)
{
// Do nothing.
}
else if (model == null || model.GetType() != modelType)
{
// Self dispose when form indicates model change.
value.ValueChanged = null;
return;
}
if (action == ValidationAction.ValidateField)
{
ModelState.Validate(model, propertyKey);
}
else
{
ModelState.ClearValidationErrors(model, propertyKey);
}
};
}
return(value);
};
}
}
else
{
var literal = new PlainObject(argument);
argumentProvider = context => literal;
}
BindingProxy ValueProvider(IResourceContext context)
{
var key = new BindingProxyKey(propertyKey);
if (context.TryFindResource(key) is BindingProxy proxy)
{
return(proxy);
}
proxy = new BindingProxy();
context.AddResource(key, proxy);
return(proxy);
}
Func <IResourceContext, IBoolProxy> isEnforcedProvider;
switch (attribute.When)
{
case null:
isEnforcedProvider = context => new PlainBool(true);
break;
case string expr:
var boundExpression = BoundExpression.Parse(expr);
if (!boundExpression.IsSingleResource)
{
throw new ArgumentException(
"The provided value must be a bound resource or a literal bool value.", nameof(attribute));
}
isEnforcedProvider = context => boundExpression.GetBoolValue(context);
break;
case bool b:
isEnforcedProvider = context => new PlainBool(b);
break;
default:
throw new ArgumentException(
"The provided value must be a bound resource or a literal bool value.", nameof(attribute));
}
Func <IResourceContext, IErrorStringProvider> errorProvider;
var message = attribute.Message;
if (message == null)
{
switch (attribute.Condition)
{
case Must.BeGreaterThan:
message = "Value must be greater than {Argument}.";
break;
case Must.BeGreaterThanOrEqualTo:
message = "Value must be greater than or equal to {Argument}.";
break;
case Must.BeLessThan:
message = "Value must be less than {Argument}.";
break;
case Must.BeLessThanOrEqualTo:
message = "Value must be less than or equal to {Argument}.";
break;
case Must.BeEmpty:
message = "@Field must be empty.";
break;
case Must.NotBeEmpty:
message = "@Field cannot be empty.";
break;
default:
message = "@Invalid value.";
break;
}
}
{
var func = new Func <IResourceContext, IProxy>(ValueProvider);
var boundExpression = BoundExpression.Parse(message, new Dictionary <string, object>
{
["Value"] = func,
["Argument"] = argumentProvider
});
if (boundExpression.IsPlainString)
{
var errorMessage = boundExpression.StringFormat;
errorProvider = context => new PlainErrorStringProvider(errorMessage);
}
else
{
if (boundExpression.Resources.Any(
res => res is DeferredProxyResource resource && resource.ProxyProvider == func))
{
errorProvider =
context => new ValueErrorStringProvider(boundExpression.GetStringValue(context),
ValueProvider(context));
}
public static IValueProvider GetResource <T>(object value, object defaultValue,
Func <string, object> deserializer)
{
if (value == null)
{
return(new LiteralValue(defaultValue));
}
if (value is string expression)
{
var boundExpression = BoundExpression.Parse(expression);
switch (boundExpression.Resources.Count)
{
case 0:
return(new LiteralValue(
deserializer != null && boundExpression.StringFormat != null
? deserializer(boundExpression.UnescapedStringFormat())
: boundExpression.UnescapedStringFormat()));
case 1 when boundExpression.StringFormat == null:
return(new CoercedValueProvider <T>(boundExpression.Resources[0], defaultValue));
default:
if (typeof(T) == typeof(bool))
{
var expr = boundExpression.UnescapedStringFormat();
string converter = null;
for (var i = expr.Length - 1; i >= 0; i--)
{
var c = expr[i];
if (c == '}')
{
var next = i > 0 ? expr[i - 1] : '\0';
if (next == '}')
{
i--;
continue;
}
break;
}
if (c == '|')
{
var next = i > 0 ? expr[i - 1] : '\0';
if (next == '|')
{
// This will throw later anyway...
break;
}
converter = expr.Substring(i + 1);
expr = expr.Substring(0, i);
break;
}
}
var ast = BooleanExpression.Parse(expr);
return(new MultiBooleanBinding(ast, boundExpression.Resources, converter));
}
throw new ArgumentException(
$"The expression '{expression}' is not a valid resource because it does not define a single value source.",
nameof(value));
}
}
if (value is T)
{
return(new LiteralValue(value));
}
throw new ArgumentException(
$"The provided value must be a bound resource or a literal value of type '{typeof(T).FullName}'.",
nameof(value));
}