public static BindingProxy GetValueProxy(IResourceContext context, string propertyKey)
{
var key = new BindingProxyKey(propertyKey);
if (context.TryFindResource(key) is BindingProxy proxy)
{
return(proxy);
}
proxy = new BindingProxy();
context.AddResource(key, proxy);
return(proxy);
}
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));
}