WPF Data Validation - Exception, IDataErrorInfo, ValidationRule, & Annotations

[@anrodse]

Great explanation! Thank you so much.
BTW: Thanks for the Ctrl+. tip. I knew it was possible but I didn't know the combination.

[@ivandrofly]

10:09 I think binding the tooltip directly with the dictionary will throw an exception when there is no error on the property - you only show when there are errors.
Ps: There is also another interface for validation INotifyOnDataErrroInfo which I think is also very powerful

[@freddyflares2757]

I prefer the IDataErrorInfo interface, but an issue in all cases is if you have a Textbox backed by a numeric property with a OneWayToSource binding and the user enters an invalid string. It's not easy to communicate that back to the ViewModel in a Command's CanExecute handler for example. What I did was make a custom ValueConverter that TryParses the string to an int or -1 if error and treat -1 as an invalid value.

[@kobayashilin3302]

Really good video, it helps a lot, thank you.

[@richardkerr2009]

Great explanation and with different implementations - I've ended up using
a combination of these to fit the needs of my view. Thanks for taking time to put these videos together.

[@hazemelamir2083]

many thanks for your valuable tutorial

[@vinuhosanagar1]

Thanks much for your tutorials. We need more and more from you :)

[@ToskersCorner]

How was the video quality? I just recently realized I had been recording with a downscale to 720p, so in this video I changed to 1080p. Not sure if the extra file size is worth it or not.

[@vinuhosanagar1]

ToskersCorner video quality is nice. However getting 720p only

[@Gazcan]

How can I display the error message in the textbox when using exceptions?

[@dhruvpanchal9010]

Great Explanation !

[@DoctorMGL]

any way to manage ( *value could not be converted* ) Error message ? that is fired by ( idataErrorinfo )

[@yeagor541]

Is there any possibility to also bind button enable/disable status with textblock changing?

[@lawkaijian618]

Why my OnPropertyChanged got error at IDataErrorInfo?Please help!

[@hamarasansarharsh]

which one is best performance wise?

[@surfsoul8660]

Nice video.
I have a little question when I tried the ValidationByDataAnnotation method, Unable to cast object of type 'System.Int32' to type 'System.Array' gave me this error, what have I done wrong?

[@gundolflinda8434]

Using the IDataErrorInfo approach together with an ErrorTemplate with seems to work. Am I right that ErrorCollection won't be necessary in this case?

[@nemethistvan1892]

How can i set the MinimumCharacters field from source code (the value is 5 in the 14:29 picture in the video). I want to set the rule's value from a value what was read out from an xml file at startup.
I can't solve this huge problem, and it is quite urgent for me.
Thanks in advance.

[@erikjansen9149]

ErrorCollection will keep old messages. Where do you clear the collection?

[@gundolflinda8434]

I firstly thought so aswell. But everytime that "name" validates successfully (i.e. result == null after value of name get checked) we still assign result ( = null ) to ErrorCollection[name], therefore resetting its error message.

[@Danger418]

Is it possible to disable/enable Submit button based on these validation errors?

[@Trust_Me_Im_An_Engineer]

Try using a multivalue converter for multiple input fields and then handling the logic inside of the converter.

[@pk2068]

well done. Simple, short, clear. No fuss, no wasting time. Tip to the point. And also your english is understandable.

[@sashabelyy7528]

14:02 If you wanna property validates on start need set ValidationRule property ValidatesOnTargetUpdate="True". In this case 13:50 need write:

[@daled3502]

Are you able to demo the validation being triggered by a button press....

[@appspointco941]

Great explanation! Thank you so much.

[@domeanterai]

annotation more simple & clean I think.. good video .. Thanks

[@hanimajali7581]

Great Video... I like the annotation because it is like what I use in MVC. Thank you!

[@billymumby9821]

How would you get access to a validation errors in example 3 in your viewmodel?

[@ToskersCorner]

Can you timestamp that spot to which you are referring?

[@joshualatusia4858]

@@ToskersCorner I think he means example 3 which starts at 10:39 - The minimum character rule.

[@andresreloir4076]

How would you implement a default validation when using the IDataErrorInfo interface? I would like to avoid a giant switch statement.

[@solvedplus858]

very cool but how can we bind error collection in ex2 to the error template in ex3?

[@oussamasethoum2755]

Thank you very much, this is very educative

[@nandinik7816]

Finally found a good video on validation. Thank you

[@sergiotardo]

Excelent video!!!! thanks

[@talkathiriify]

Thank you very much for all your video series

[@PaulCuenin]

very helpful. Thanks

[@suriyadexter9674]

How to do it in the combo box??

[@longuinni]

Really nice. I'm learning a lot from you. Keep going, you have a valuable content here.

[@joshuasafabre1202]

just thinking. how to clear TextBox After submitting.

[@Danger418]

Well the simple way of doing it would be to set the TextBox.Text property to empty in your submit Click Event. Something like this:
private void btnSubmit_Click(object sender, RoutedEventArgs e)
{
txbUsername.Text = "";
}