Force IDataErrorInfo validation

Question

I have two controls on some panel: textbox and combobox:

<TextBox Text="{Binding ShapeName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />

<ComboBox SelectedItem="{Binding ActiveStageViewModel, Mode=OneWayToSource, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}" />

I need to force idataerrorinfo validation for textbox, when I select something on combobox. How to do that?

The code from viewmodel:

string IDataErrorInfo.this[string propertyName]
    {
      get
      {
        var error = string.Empty;

        if (propertyName == Expression.GetPropertyName(() => ActiveStageViewModel))
        {
          // TODO: Add functionality to force ShapeName property validation
          return error;
        }

        if (propertyName == Expression.GetPropertyName(() => ShapeName))
        {
          error = ValidateShapeName();
        }

        TooltipMessage = error;
        return error;
      }
    }

Vinculum

Answer 1

Just raise the NotifyPropertyChanged event for the property you want to validate or if you are in .NET 4.5 or Silverlight 4 use the INotityDataErrorInfo.

Edea

yea...NotifyPropertyChanged works) I have tried before, but forgot about two way mode... – Vinculum

I've used [AlsoNotifyFor("ShapeName")] over ActiveStageViewModel – Caucasia

It kinda works... In my case I have a TabControl and in the last tab when user clicks save for the first time, I raise NotifyPropertyChanged and the error is shown. However, when I go back to other tab, and switch back again to the last tab, raising NotifyPropertyChanged does not work, no error template is shown. Any insights? – Basle

@Basle You have a solution to this yet? – Ricardaricardama

@Basle Ok I found a solution in case you need it so link – Ricardaricardama

Answer 2

Worth remembering also that you can raise NotifyPropertyChanged with String.Empty property. This will force validation of all properties at that level. Can be useful at times.

Humiliation