// A method that simply takes an ObservableValidator
// and returns the first error from it if one exists,
// otherwise returning an empty string. Unfortunately,
// WinUI does not support input validation on the
// UI elements, so we couldn't show the user per-field
// validation, so this is the next best thing - we simply
// get the first error and show them it.
public static string GetFirstError(this ObservableValidator validator)
{
// We get the errors from the validator, passing in null
// as the property name (this returns errors for every property)
// then we get the first one, or null if none exist.
var firstError = validator.GetErrors(null).FirstOrDefault();
// We then either return an empty string
// or the error message depending on if
// it exists.
return(firstError != null ? firstError.ErrorMessage : "");
}
public static void ValidateProperty(ObservableValidator instance, object?value, string propertyName)
{
instance.ValidateProperty(value, propertyName);
}