bool TryConvert(BindingExpressionPart part, ref object value, Type convertTo, bool toTarget)
{
if (value == null)
{
return(true);
}
if ((toTarget && _targetProperty.TryConvert(ref value)) || (!toTarget && convertTo.IsInstanceOfType(value)))
{
return(true);
}
object original = value;
try
{
var stringValue = value as string ?? string.Empty;
// see: https://bugzilla.xamarin.com/show_bug.cgi?id=32871
// do not canonicalize "*.[.]"; "1." should not update bound BindableProperty
if (stringValue.EndsWith(".", StringComparison.Ordinal) && DecimalTypes.Contains(convertTo))
{
value = original;
return(false);
}
// do not canonicalize "-0"; user will likely enter a period after "-0"
if (stringValue == "-0" && DecimalTypes.Contains(convertTo))
{
value = original;
return(false);
}
value = Convert.ChangeType(value, convertTo, CultureInfo.InvariantCulture);
return(true);
}
catch (InvalidCastException)
{
value = original;
return(false);
}
catch (FormatException)
{
value = original;
return(false);
}
catch (OverflowException)
{
value = original;
return(false);
}
}
internal static bool TryConvert(ref object value, BindableProperty targetProperty, Type convertTo, bool toTarget)
{
if (value == null)
{
return(!convertTo.GetTypeInfo().IsValueType || Nullable.GetUnderlyingType(convertTo) != null);
}
try
{
if ((toTarget && targetProperty.TryConvert(ref value)) || (!toTarget && convertTo.IsInstanceOfType(value)))
{
return(true);
}
}
catch (InvalidOperationException)
{ //that's what TypeConverters ususally throw
return(false);
}
object original = value;
try
{
var stringValue = value as string ?? string.Empty;
// see: https://bugzilla.xamarin.com/show_bug.cgi?id=32871
// do not canonicalize "*.[.]"; "1." should not update bound BindableProperty
if (stringValue.EndsWith(".", StringComparison.Ordinal) && DecimalTypes.Contains(convertTo))
{
value = original;
return(false);
}
// do not canonicalize "-0"; user will likely enter a period after "-0"
if (stringValue == "-0" && DecimalTypes.Contains(convertTo))
{
value = original;
return(false);
}
convertTo = Nullable.GetUnderlyingType(convertTo) ?? convertTo;
value = Convert.ChangeType(value, convertTo, CultureInfo.InvariantCulture);
return(true);
}
catch (Exception ex) when(ex is InvalidCastException || ex is FormatException || ex is InvalidOperationException || ex is OverflowException)
{
value = original;
return(false);
}
}
internal void SetValueCore(BindableProperty property, object value, SetValueFlags attributes, SetValuePrivateFlags privateAttributes)
{
bool checkAccess = (privateAttributes & SetValuePrivateFlags.CheckAccess) != 0;
bool manuallySet = (privateAttributes & SetValuePrivateFlags.ManuallySet) != 0;
bool silent = (privateAttributes & SetValuePrivateFlags.Silent) != 0;
bool fromStyle = (privateAttributes & SetValuePrivateFlags.FromStyle) != 0;
bool converted = (privateAttributes & SetValuePrivateFlags.Converted) != 0;
if (property == null)
{
throw new ArgumentNullException("property");
}
if (checkAccess && property.IsReadOnly)
{
Debug.WriteLine("Can not set the BindableProperty \"{0}\" because it is readonly.", property.PropertyName);
return;
}
if (!converted && !property.TryConvert(ref value))
{
Log.Warning("SetValue", "Can not convert {0} to type '{1}'", value, property.ReturnType);
return;
}
if (property.ValidateValue != null && !property.ValidateValue(this, value))
{
throw new ArgumentException("Value was an invalid value for " + property.PropertyName, "value");
}
if (property.CoerceValue != null)
{
value = property.CoerceValue(this, value);
}
BindablePropertyContext context = GetOrCreateContext(property);
if (manuallySet)
{
context.Attributes |= BindableContextAttributes.IsManuallySet;
context.Attributes &= ~BindableContextAttributes.IsSetFromStyle;
}
else
{
context.Attributes &= ~BindableContextAttributes.IsManuallySet;
}
if (fromStyle)
{
context.Attributes |= BindableContextAttributes.IsSetFromStyle;
}
// else omitted on purpose
bool currentlyApplying = _applying;
if ((context.Attributes & BindableContextAttributes.IsBeingSet) != 0)
{
Queue <SetValueArgs> delayQueue = context.DelayedSetters;
if (delayQueue == null)
{
context.DelayedSetters = delayQueue = new Queue <SetValueArgs>();
}
delayQueue.Enqueue(new SetValueArgs(property, context, value, currentlyApplying, attributes));
}
else
{
context.Attributes |= BindableContextAttributes.IsBeingSet;
SetValueActual(property, context, value, currentlyApplying, attributes, silent);
Queue <SetValueArgs> delayQueue = context.DelayedSetters;
if (delayQueue != null)
{
while (delayQueue.Count > 0)
{
SetValueArgs s = delayQueue.Dequeue();
SetValueActual(s.Property, s.Context, s.Value, s.CurrentlyApplying, s.Attributes);
}
context.DelayedSetters = null;
}
context.Attributes &= ~BindableContextAttributes.IsBeingSet;
}
}