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;
      }
    }

bitbonk · Accepted Answer · 2012-11-14T12:39:21.120

23

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.

edited Nov 14 '12 at 12:39

answered Nov 14 '12 at 12:33

bitbonk

48,890
37
186
278

yea...NotifyPropertyChanged works) I have tried before, but forgot about two way mode... – Witcher Nov 14 '12 at 14:04
I've used [AlsoNotifyFor("ShapeName")] over ActiveStageViewModel – Martina May 30 '16 at 15:55
1

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? – JobaDiniz Sep 14 '16 at 20:46
@JobaDiniz You have a solution to this yet? – EpicKip Sep 07 '18 at 08:44
1

@JobaDiniz Ok I found a solution in case you need it [so link](https://stackoverflow.com/questions/9907075/textbox-with-validation-loses-errortemplate-on-tab-change) – EpicKip Sep 07 '18 at 09:32

score 16 · Answer 2 · answered Nov 14 '12 at 14:15

16

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.

answered Nov 14 '12 at 14:15

Paul Marques

604
4
15

Force IDataErrorInfo validation

2 Answers2

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