Add and remove textbox at runtime in mvc3 - asp.net-mvc-3

Question

In my page there is one textbox by default and one add button beside it. I need to add the another textbox when user click Add button. And there should be two buttons Add and Remove beside newly added text box. And same process goes on i.e., user can add Textbox using Add button and remove it using remove button.
I am new to mvc 3 so i am confused how to proceed. Is there any way like placeholder in asp.net so that we can add control at runtime.
Any suggestion and idea will be helpful to me

Answer 1

MVC is a very "hands-off" framework compared to Web Forms, so you're free to add the new textboxes how you like. Note that "controls" don't exist in MVC.
Here's how I'd do it:
Model:
class MyModel {
public Boolean AddNewTextBox { get; set; }
public List<String> MultipleTextBoxes { get; set; } // this stores the values of the textboxes.
}
View (I prefer the Web Forms view engine, I'm not a fan of Razor):
<% for(int i=0;i<Model.MultipleTextBoxes.Count;i++) { %>
<%= Html.TextBoxFor( m => m.MultipleTextBoxes[i] ) /* this might look like magic to you... */ %>
<% } %>
<button type="submit" name="AddNewTextbox" value="true">Add New Textbox</button>
<button type="submit">Submit form</button>
Controller:
[HttpPost]
public ActionResult MyAction(MyModel model) {
if( model.AddNewTextBox ) model.MultipleTextBoxes.Add("Yet another");
else if( ModelState.IsValid ) {
// your regular processing
}
}
You can also add more textboxes with Javascript and it work perfectly fine. All that matters is the HTML input elements. There's no cryptic viewstate. MVC is stateless.
Note that because I used <button type="submit"> my example will not work reliably in Internet Explorer 6-8 (sucks, I know), but you can replace them with <input type="submit"> with no ill-effects.

Answer 2

This requires some Javascript/JQuery... The following is a sketch only, but will hopefully be useful as a general approach.
The remove button
You want to render a button that can target its own container for removal. To do that, use some markup like this:
<div class="item-container">
<input type="button" onclick="removeItem(this)" />
</div>
And the Javascript for removeItem:
<script>
function removeItem(element) {
// get the parent element with class "item-container" and remove it from the DOM
$(element).find(".item-container").remove();
}
</script>
The add button
You could either use a partial view with Ajax, or use straight Javascript; which one is best likely depends on whether you need a round-trip to the server to create a new item. Let's say you need to go the the server to generate a new ID or something.
First, create a partial view and corresponding controller action; this should contain the remove button as above, as well as the text box and add button.
Now, create an Ajax form on your main page that gets invoked when you click Add:
<script src="#Url.Content("~/Scripts/jquery.unobtrusive-ajax.min.js")" type="text/javascript"></script>
#using (Ajax.BeginForm("New", new AjaxOptions() { UpdateTargetId="ajaxTarget", HttpMethod = "GET" })) {
<input type='submit' value='Add New' />
}
<div id="ajaxTarget"></div>
This code fetches your partial view (from the action New in the current controller) and adds the result to the ajaxTarget element.
Note The Ajax form requires Unobtrusive Ajax, which you can install via Nuget: Install-Package JQuery.Ajax.Unobtrusive.