P is for Programming

Retrieve Views and Submit Forms with Ajax, JQuery and MVC

November 19, 2009

In my previous post I was using Ajax to retrieve Json data and update the DOM using JavaScript.  While this is pretty useful you will often find your application quickly becomes JavaScript-heavy and difficult to maintain.  I’m going to illustrate using JQuery and the MVC Ajax libraries to simplify this process.

Retrieving a view using Ajax

The first thing I’m going to do is to change the view I did in my last post.  Instead of retrieving Json and manually updating the DOM using JavaScript I’m going to use partial views.  This way the difficult work gets done on the server and is less error-prone and easier to maintain.

The first step is to split my view into a number of partial views and introduce placeholders for the details and comments that I load once a widget is selected.

<h2>Select a Widget</h2>

<div id="widgetsDiv">
    <% Html.RenderPartial("Widgets", Model); %>
</div>

<br />

<h2>Details</h2>
<div id="widgetDetailsDiv"></div>

<h2>Comments</h2>
<div id="widgetCommentsDiv"></div>

I now want to be able to update the list of widgets via Ajax.  Because I put the list into a partial view I simply need to add another action on my controller for retrieving this partial view.

[AcceptVerbs(HttpVerbs.Get)]
public ActionResult GetWidgets()
{
    return PartialView("Widgets", widgetService.GetWidgets());
}

The last step is to call this action with JQuery and update the DOM.

jQuery.get(rootPath + "Example/GetWidgets", function(response) {
    $("#widgetsDiv").html(response);
});

I can load the details and comments in a similar fashion.

jQuery.get(rootPath + "Example/WidgetDetails?widgetId=" + selectedWidgetId, function(response) {
    $("#widgetDetailsDiv").html(response);
});

jQuery.get(rootPath + "Example/WidgetComments?widgetId=" + selectedWidgetId, function(response) {
    $("#widgetCommentsDiv").html(response);
});   

Which is really very simple.  Now let’s allow the user to add widgets.

Form submission using Ajax

To allow adding widgets I created a simple form to handle the data entry.  The only tricky bit is that I want to submit this form using Ajax.  I’m going to use the built-in MVC Ajax libraries to submit the form.

<% using (Ajax.BeginForm("Add", "Example", new AjaxOptions { HttpMethod = FormMethod.Post.ToString(), OnComplete = "widgetAdded" } )) { %>

    <label>Name:</label>
    <input type="text" id="Name" name="Name" />

    <label>Attribute:</label>
    <input type="text" id="Attribute" name="Attribute" />
    <input type="text" id="Value" name="Value" />

    <label>Comment:</label>
    <input type="text" id="Comment" name="Comment" />

    <input type="submit" value="Add" />

<% } %>

It’s possible to do this with JQuery but I find it much easier with the MVC Ajax libraries.  Now we simply need to refresh the list of widgets in the OnComplete method (using the routing I showed earlier) and we’re done.

I have attached the code here.  Happy coding.

Tags: Ajax, C#, MVC