PropertyChangedEventArgs FormatException

Question

I have next XAML:

<TextBlock Text="{Binding Path=Parameter.LocalizedName}"/>

And this code in my View Model:

public FilterParameter Parameter
{
  get
  {
    return this._Parameter;
  }
  set
  {
    this._Parameter = value;
    base.RaisePropertyChanged("Parameter");
  }
}

I do

this.Parameter = newParameter

Why I do I get

FormatException (Input string was not in a correct format.)

After a call to PropertyChangedEventHandler ?

http://oi45.tinypic.com/11trceg.jpg

---

Inner exception is null. Stack trace loook like

mscorlib.dll!System.Number.StringToNumber(string str, System.Globalization.NumberStyles options, ref System.Number.NumberBuffer number, System.Globalization.NumberFormatInfo info, bool parseDecimal) + 0xf7 bytes 
mscorlib.dll!System.Number.ParseInt32(string s, System.Globalization.NumberStyles style, System.Globalization.NumberFormatInfo info) + 0x92 bytes   
mscorlib.dll!string.System.IConvertible.ToInt32(System.IFormatProvider provider) + 0x2f bytes   
mscorlib.dll!System.Convert.ChangeType(object value, System.Type conversionType, System.IFormatProvider provider) + 0x1ff bytes 
PresentationFramework.dll!MS.Internal.Data.SystemConvertConverter.Convert(object o, System.Type type, object parameter, System.Globalization.CultureInfo culture) + 0x11 bytes  
PresentationFramework.dll!MS.Internal.Data.DynamicValueConverter.Convert(object value, System.Type targetType, object parameter, System.Globalization.CultureInfo culture) + 0x51 bytes 
PresentationFramework.dll!System.Windows.Controls.Primitives.Selector.VerifyEqual(object knownValue, System.Type knownType, object itemValue, MS.Internal.Data.DynamicValueConverter converter) + 0x64 bytes    
PresentationFramework.dll!System.Windows.Controls.Primitives.Selector.FindItemWithValue(object value, out int index) + 0x1f7 bytes  
PresentationFramework.dll!System.Windows.Controls.Primitives.Selector.SelectItemWithValue(object value) + 0x3e bytes    
PresentationFramework.dll!System.Windows.Controls.Primitives.Selector.CoerceSelectedValue(System.Windows.DependencyObject d, object value) + 0x91 bytes 
WindowsBase.dll!System.Windows.DependencyObject.ProcessCoerceValue(System.Windows.DependencyProperty dp, System.Windows.PropertyMetadata metadata, ref System.Windows.EntryIndex entryIndex, ref int targetIndex, ref System.Windows.EffectiveValueEntry newEntry, ref System.Windows.EffectiveValueEntry oldEntry, ref object oldValue, object baseValue, object controlValue, System.Windows.CoerceValueCallback coerceValueCallback, bool coerceWithDeferredReference, bool coerceWithCurrentValue, bool skipBaseValueChecks) + 0x55 bytes   
WindowsBase.dll!System.Windows.DependencyObject.UpdateEffectiveValue(System.Windows.EntryIndex entryIndex, System.Windows.DependencyProperty dp, System.Windows.PropertyMetadata metadata, System.Windows.EffectiveValueEntry oldEntry, ref System.Windows.EffectiveValueEntry newEntry, bool coerceWithDeferredReference, bool coerceWithCurrentValue, System.Windows.OperationType operationType) + 0x247 bytes   
WindowsBase.dll!System.Windows.DependencyObject.InvalidateProperty(System.Windows.DependencyProperty dp, bool preserveCurrentValue) + 0xd1 bytes    
PresentationFramework.dll!System.Windows.StyleHelper.InvalidateDependents(System.Windows.Style ownerStyle, System.Windows.FrameworkTemplate frameworkTemplate, System.Windows.DependencyObject container, System.Windows.DependencyProperty dp, ref MS.Utility.FrugalStructList<System.Windows.ChildPropertyDependent> dependents, bool invalidateOnlyContainer) + 0x79 bytes   
PresentationFramework.dll!System.Windows.StyleHelper.OnBindingValueInTemplateChanged(object sender, MS.Internal.Data.BindingValueChangedEventArgs e) + 0xe2 bytes   
PresentationFramework.dll!System.Windows.Data.BindingExpressionBase.ChangeValue(object newValue, bool notify) + 0x94 bytes  
PresentationFramework.dll!System.Windows.Data.BindingExpression.TransferValue(object newValue, bool isASubPropertyChange) + 0x40c bytes 
PresentationFramework.dll!System.Windows.Data.BindingExpression.ScheduleTransfer(bool isASubPropertyChange) + 0x3a bytes    
PresentationFramework.dll!MS.Internal.Data.ClrBindingWorker.NewValueAvailable(bool dependencySourcesChanged, bool initialValue, bool isASubPropertyChange) + 0x60 bytes 
PresentationFramework.dll!MS.Internal.Data.PropertyPathWorker.UpdateSourceValueState(int k, System.ComponentModel.ICollectionView collectionView, object newValue, bool isASubPropertyChange) + 0x211 bytes 
PresentationFramework.dll!MS.Internal.Data.ClrBindingWorker.OnSourcePropertyChanged(object o, string propName) + 0x85 bytes 
PresentationFramework.dll!MS.Internal.Data.PropertyPathWorker.OnPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e) + 0x68 bytes   
WindowsBase.dll!System.Windows.WeakEventManager.ListenerList<System.ComponentModel.PropertyChangedEventArgs>.DeliverEvent(object sender, System.EventArgs e, System.Type managerType) + 0x12c bytes 
WindowsBase.dll!System.ComponentModel.PropertyChangedEventManager.OnPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs args) + 0x40c bytes   
>   MyApp.Framework.Core.dll!MyApp.Framework.Core.NotifyObject.RaisePropertyChanged(string propertyName) Line 45 + 0x32 bytes   C# 

Answer 1

WPF is trying to convert System.String to System.Int32 and it fails with FormatException.

You should set custom IValueConverter to your Binding to handle this scenario by, for example, returning some default int value, if string cannot be parsed to int.