RavenDb - Write query and select item where it's propertyName equals a string

Question

Is it possible to write a query and select an item where its propertyName equals a string?

I want to pass in a string to a method, where my string holds the value of a propertyName. And then use it in a query to select my property that equals that string. Is this possible?

I know I'm not writing any code here, just asking if this is possible to do.

EDIT: Ok this as my solution a come up wth so far, and I know, it's far from a good solution. But I will put here and if you can give me a better solution, feel free to do it. Any help is a appreciated!

This is one of the Raven-document I could work with:

  {
  "WelcomeHeader": "header",
  "WelcomeText": "some text",
  "Template": {
    "Id": "RouteConfigTemplates/1",
    "Name": "Index",
    "Controller": "Home",
    "Action": "Index",
    "View": "Index",
    "ContentPageType": "Core_StudioL.Models.IndexCorePage, Core_StudioL"
  },
  "Url": "/"
  "Title": "Start"
  }

Im my view a have a couple of WYSIWYG-editors, and each time I push the save button on one of my editors i sending the parameters to this mvc-controller-method below:

string model : is my whole model in json-format as string.

string activeId : is the id of the passed WYSIWYG-editors div (activeId = The sent propertys propertyName)

string contentToUpdate : is the value I want to update

[ValidateInput(false)]
    public JsonResult SaveContent(string model, string activeId, string contentToUpdate)
    {
        //parse model to json
        var modelAsJson = JObject.Parse(model);

        //if the property-name == item.key, replace it
        foreach (var item in modelAsJson)
        {
            if (item.Key == activeId)
            {
                item.Value.Replace(contentToUpdate);
            }
        }

        //find the right contentPageType
        string cType = modelAsJson["Template"]["ContentPageType"].ToString();

        //convert back to string
        string newModel = modelAsJson.ToString(Formatting.None);

        //here I need to have many if-statments (not an optimal solution) to pick out the right contentPageType, here is a example of one of them.
        //The problem here
        if (cType.Equals("Core_StudioL.Models.IndexCorePage, Core_StudioL"))
        {
            var jsonSerializer = new JavaScriptSerializer();
            var modelAsCorrectModel = jsonSerializer.Deserialize<IndexCorePage>(newModel);

            //Here I'm having problem to update a single value, because the values sent in to the controller could be any..
            //So my ugly solution here is to delete the whole document from raven, and then save a new one with the updated values. If a just could only save the `string contentToUpdate`
            //
            var page = RavenSession.Load<CorePage>(modelAsCorrectModel.Id);
            RavenSession.Delete(page);
            RavenSession.SaveChanges();

            RavenSession.Store(modelAsCorrectModel);
            RavenSession.SaveChanges();

            var modelToReturn = new JavaScriptSerializer().Serialize(modelAsCorrectModel);


            return Json(modelToReturn);
        }

        return null;
    }

by doing it this way, my model in the razor-view never gets updated before I reload the page. That means: If a save on of my WYSIWYG-editors, it's content gets updated to ravendb. But if I save another one without refreshing the page after I saved the first one. Then just that another one gets updated. Because the model sent in to the save-method is still the first model sent in to the view. So: the first one saved, then gets overwritten by the original Model, because it still holds the original models values!