How to programmatically add an error message to the MVC ValidationSummary

mvc-add-msg-to-validation-summary.js

// Set up an associative array for the error messages.  The keys must be the exact name of the 
// controls that need to have the error message displayed.
var errorArray = {
  SomeProperty: "'SomeProperty' has shit the bed",
  SomeOtherProperty: "Whoa - TWO errors?  You are up the creek"
};

// Show the errors next to their associated controls
$('#form-to-validate').validate().showErrors(errorArray);

// Add the error messages to the validation summary.
// '[data-valmsg-summary]' is the name of the div that MVC injects into the markup; this shouldn't
// have to change when implementing this.
var validationSummary = $('[data-valmsg-summary]');
validationSummary.addClass('validation-summary-errors')
  .removeClass('validation-summary-valid');

$.each(errorArray, function(index, item) {
    // add each error
    validationSummary.children('ul').append($('<li class="my-custom-error"></li>').text(item));
});

// OPTIONAL: Scroll to the top of the form to the top of the screen so the validation summary
// is visible.
$('#outlineContent').scrollTop(0);