R – Dealing with ASP.Net Custom Controls in MVC

asp.netasp.net-mvccustom-server-controls

I have looked around on the Internet trying to answer this question. It seems to be kind of complicated though! Seems to come up with all sorts of different topics such as the HtmlHelper and other stuff.

Basically. How can you use custom controls with MVC? In a way that avoids doing anything that is frowned upon.

Also, Is it true that with MVC you have to put some simple logic IN THE PAGE? Isn't that what we should be getting away from?

Update: So, Seems you cannot use controls which depend on anything which MVC does away with, such as the postback events and viewstate. Can you make your own then? A control which does only rendering of course.

Best Answer

Can you use ASP.NET controls? Maybe. If the control does not use ViewState or postback events, it will probably work. For example, the LoginView control works just fine. Telerik supports ASP.NET MVC with some of their controls. On the other hand, if the control needs either ViewState or postbacks, then it just isn't going to work. Controls with data binding aren't ideal, since you typically have to use code behind him up. But they will work, if you add code behind.

On the other hand, controls with no knowledge of ASP.NET (such as the jQuery UI controls) work very well.

No, you don't have to put your logic in the page. You just don't put it on a code behind page, either. Instead, use helper methods.

Related Solutions

Asp.net-mvc – Can an ASP.NET MVC controller return an Image

Use the base controllers File method.

public ActionResult Image(string id)
{
    var dir = Server.MapPath("/Images");
    var path = Path.Combine(dir, id + ".jpg"); //validate the path for security or use other means to generate the path.
    return base.File(path, "image/jpeg");
}

As a note, this seems to be fairly efficient. I did a test where I requested the image through the controller (http://localhost/MyController/Image/MyImage) and through the direct URL (http://localhost/Images/MyImage.jpg) and the results were:

MVC: 7.6 milliseconds per photo
Direct: 6.7 milliseconds per photo

Note: this is the average time of a request. The average was calculated by making thousands of requests on the local machine, so the totals should not include network latency or bandwidth issues.

Asp.net-mvc – How to handle checkboxes in ASP.NET MVC forms

Html.CheckBox is doing something weird - if you view source on the resulting page, you'll see there's an <input type="hidden" /> being generated alongside each checkbox, which explains the "true false" values you're seeing for each form element.

Try this, which definitely works on ASP.NET MVC Beta because I've just tried it.

Put this in the view instead of using Html.CheckBox():

<% using (Html.BeginForm("ShowData", "Home")) {  %>
  <% foreach (var o in ViewData.Model) { %>
    <input type="checkbox" name="selectedObjects" value="<%=o.Id%>">
    <%= o.Name %>
  <%}%>
  <input type="submit" value="Submit" />
<%}%>

Your checkboxes are all called selectedObjects, and the value of each checkbox is the GUID of the corresponding object.

Then post to the following controller action (or something similar that does something useful instead of Response.Write())

public ActionResult ShowData(Guid[] selectedObjects) {
    foreach (Guid guid in selectedObjects) {
        Response.Write(guid.ToString());
    }
    Response.End();
    return (new EmptyResult());
}

This example will just write the GUIDs of the boxes you checked; ASP.NET MVC maps the GUID values of the selected checkboxes into the Guid[] selectedObjects parameter for you, and even parses the strings from the Request.Form collection into instantied GUID objects, which I think is rather nice.

Best Answer

Related Solutions

Asp.net-mvc – Can an ASP.NET MVC controller return an Image

Asp.net-mvc – How to handle checkboxes in ASP.NET MVC forms

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