Validate user inputs in PropertySheet

[AbelPerez]

I followed the sample here ProGuide Custom settings · Esri/arcgis-pro-sdk Wiki · GitHub and have added my own add-in settings to the backstage. I've binded several properties to the UI and it works great. I have a textbox where the user can browse to a folder where our company's data exists. If the user inputs an invalid folder I wanted to change the backcolor of the textbox and set the OK button to disabled until the input is fixed. A similar thing is done with the Layout options.

Ive looked in the community samples and looked at the Pro SDK and cant find anything. Where would I add my validation logic to mimic the existing Layout options?

[GKmieliauskas]

Hi Abel,

This is the WPF stuff. Look here:

https://docs.microsoft.com/en-us/dotnet/framework/wpf/data/how-to-implement-binding-validation

[AbelPerez]

Yes Im aware of the validation binding. Thank You. What I am asking is how we tap into the Pro Settings OK button to disable it when something is not valid.

[GKmieliauskas]

You can disable OK button  by setting Page IsValid property, like this:

            base.IsValid = false;

[AbelPerez]

Ok I am able to bind my validation rules to the textbox. It works great! Thanks!.

But now am struggling how to get that result back to the ViewModel so I can update the IsValid of the page.

My XAML looks like this

<TextBox x:Name="txtLayerDir" TextWrapping="Wrap" VerticalAlignment="Top" Margin="10,86,36,0">
<TextBox.Text>
<Binding Path="MyAppDataDir" UpdateSourceTrigger="PropertyChanged">
<Binding.ValidationRules>
<ui:DataPathRule/>
</Binding.ValidationRules>
</Binding>
</TextBox.Text>
</TextBox>

In the ViewModel I can initialize to False and I can see that works:

Protected Overrides Function InitializeAsync() As Task

'setup the initial validity of the Page
MyBase.IsValid = False

Return Task.FromResult(0)
End Function

But how do I process updates? Just cant seem to figure that one out.

[Wolf]

In the setter for the MyAppDataDir property in the ViewModel set base.IsValid:

// for example

public string MyAppDataDir
{
   get { return _myAppDataDir; }
   set
   {
      SetProperty(ref _myAppDataDir, value, () => MyAppDataDir);
      base.IsValid = System.IO.Directory.Exists(value);
   }
}
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[AbelPerez]

Wolfgang Kaiser‌ I had something similar but didnt work. I believe its because of the Validity rules. Since the path doesnt exist then the property is never set.

Public Property MyDataDir As String
Get
  Return _myAppDataDir
End Get
Set(ByVal value As String)
  MyBase.IsValid = False
   If SetProperty(_aaAnalystAppDataDir, value, Function() MyAppDataDir) Then
    MyBase.IsModified = True
    MyBase.IsValid = True 'the property passed the validity rules
  Else
    MyBase.IsValid = False
  End If
End Set
End Property

I even changed my XAML to

<Binding Path="MyAppDataDir" UpdateSourceTrigger="PropertyChanged" ValidatesOnExceptions="True" ValidatesOnDataErrors="True" NotifyOnValidationError="True">

[AbelPerez]

So now I tried setting Validation.Error="Validation_Error" in my XAML.

Then I put the handler Validation_Error in the code behind the XAML but that's not where I want it correct?

The handler should go in the ViewModel right?

How would I then reference that in my XAML?

Private Sub Validation_Error(sender As Object, e As ValidationErrorEventArgs)
    Debug.Print("there was an error")
End Sub

[GKmieliauskas]

Hi Abel,

You need to implement IDataErrorInfo to your viewmodel

internal class ProjectSettingsViewModel : Page, IDataErrorInfo.

More info here:

https://codeblitz.wordpress.com/2009/05/08/wpf-validation-made-easy-with-idataerrorinfo/

You just need to modify content of

public string this[string columnName]

to store each control state and set base.IsValid value.

[AbelPerez]

Well I gave it a shot. I spent half a day trying to get this to work and just couldn't. I think I am missing something. The source code in your link is a dead link. Tried other sources but just couldn't get it to work.