MVC How to reaction to 2 different methods in one page - asp.net-mvc

Question

I have 2 methods : Add and Subtract. I want that when clicked Add button, the 3rd textbox displays the result of A + B; clicked "Subtract" button, the 3rd textbox displays the result of A - B.
I thought it should be a simple thing to do (because it can be done within a few lines of code in ASP.NET WebForm Application). But after trying many times and asked a few of friends, I still cannot find the solution...
#using (Html.BeginForm("Add", "MyMVC"))
{
<ol>
<li>
#Html.TextAreaFor(m => m.A)
</li>
<li><span>+ </span></li>
<li>
#Html.TextAreaFor(m => m.B)
</li>
<li><span>= </span></li>
<li>
#Html.TextAreaFor(m => m.C)
</li>
</ol>
#{
Html.RenderAction("Calculate", "MyMVC");
}
#{
Html.RenderAction("Subtract", "MyMVC");
}
}

Answer 1

The RenderAction tags aren't needed. The BeginForm extension also needs to render a form element that posts to itself.
Change your view to
#model SampleMvc.Models.SumModel
#using (Html.BeginForm())
{
<ol>
<li>
#Html.TextAreaFor(m => m.A)
</li>
<li><span>+ </span></li>
<li>
#Html.TextAreaFor(m => m.B)
</li>
<li><span>= </span></li>
<li>
#Html.TextAreaFor(m => m.C)
</li>
</ol>
<input type="submit" id="add" name="Calculate" value="Add" />
<input type="submit" id="subtract" name="Calculate" value="Subtract" />
}
Notice the name attribute on the submit inputs, this will enable the default model binder to bind to a property called Calculate.
For you View model use something similar to
public class SumModel {
public int A { get; set; }
public int B { get; set; }
public int C { get; private set; }
public string Calculate { get; set; }
public void RunCalculation() {
if (Calculate.Equals("add",StringComparison.InvariantCultureIgnoreCase)) {
C = A + B;
} else {
C = A - B;
}
}
}
Then in the controller have actions similar to:
public ActionResult Calculate() {
return View();
}
[HttpPost]
public ActionResult Calculate(SumModel sumModel) {
sumModel.RunCalculation();
return View(sumModel);
}
When the form is submitted via the click events on the submit inputs the value of the button will be auto-magically bound to the Calculate property of the SumModel.
Then when the method RunCalculation is called it uses the property to work out which operation to run against the values A and B

Answer 2

Other easy approach is , you can have the same name for the buttons. and then read it in controller.
<input type="submit" id="add" name="buttonclicked" value="Add" />
<input type="submit" id="subtract" name="buttonclicked" value="Subtract" />
[HttpPost]
public ActionResult Index(string buttonclicked, SumModel sumModel) {
if(buttonclicked=="add"){
}
else{
}
}