How do you handle multiple submit buttons in ASP.NET MVC Framework?

Here is a mostly clean attribute-based solution to the multiple submit button issue based heavily on the post and comments from Maarten Balliauw.

[AttributeUsage(AttributeTargets.Method, AllowMultiple = false, Inherited = true)]
public class MultipleButtonAttribute : ActionNameSelectorAttribute
{
    public string Name { get; set; }
    public string Argument { get; set; }

    public override bool IsValidName(ControllerContext controllerContext, string actionName, MethodInfo methodInfo)
    {
        var isValidName = false;
        var keyValue = string.Format("{0}:{1}", Name, Argument);
        var value = controllerContext.Controller.ValueProvider.GetValue(keyValue);

        if (value != null)
        {
            controllerContext.Controller.ControllerContext.RouteData.Values[Name] = Argument;
            isValidName = true;
        }

        return isValidName;
    }
}

razor:

<form action="" method="post">
 <input type="submit" value="Save" name="action:Save" />
 <input type="submit" value="Cancel" name="action:Cancel" />
</form>

and controller:

[HttpPost]
[MultipleButton(Name = "action", Argument = "Save")]
public ActionResult Save(MessageModel mm) { ... }

[HttpPost]
[MultipleButton(Name = "action", Argument = "Cancel")]
public ActionResult Cancel(MessageModel mm) { ... }

Update: Razor pages looks to provide the same functionality out of the box. For new development, it may be preferable.

Give your submit buttons a name, and then inspect the submitted value in your controller method:

<% Html.BeginForm("MyAction", "MyController", FormMethod.Post); %>
<input type="submit" name="submitButton" value="Send" />
<input type="submit" name="submitButton" value="Cancel" />
<% Html.EndForm(); %>

posting to

public class MyController : Controller {
    public ActionResult MyAction(string submitButton) {
        switch(submitButton) {
            case "Send":
                // delegate sending to another controller action
                return(Send());
            case "Cancel":
                // call another action to perform the cancellation
                return(Cancel());
            default:
                // If they've submitted the form without a submitButton, 
                // just return the view again.
                return(View());
        }
    }

    private ActionResult Cancel() {
        // process the cancellation request here.
        return(View("Cancelled"));
    }

    private ActionResult Send() {
        // perform the actual send operation here.
        return(View("SendConfirmed"));
    }

}

EDIT:

To extend this approach to work with localized sites, isolate your messages somewhere else (e.g. compiling a resource file to a strongly-typed resource class)

Then modify the code so it works like:

<% Html.BeginForm("MyAction", "MyController", FormMethod.Post); %>
<input type="submit" name="submitButton" value="<%= Html.Encode(Resources.Messages.Send)%>" />
<input type="submit" name="submitButton" value="<%=Html.Encode(Resources.Messages.Cancel)%>" />
<% Html.EndForm(); %>

and your controller should look like this:

// Note that the localized resources aren't constants, so 
// we can't use a switch statement.

if (submitButton == Resources.Messages.Send) { 
    // delegate sending to another controller action
    return(Send());

} else if (submitButton == Resources.Messages.Cancel) {
     // call another action to perform the cancellation
     return(Cancel());
}

You can check the name in the action as has been mentioned, but you might consider whether or not this is good design. It is a good idea to consider the responsibility of the action and not couple this design too much to UI aspects like button names. So consider using 2 forms and 2 actions:

<% Html.BeginForm("Send", "MyController", FormMethod.Post); %>
<input type="submit" name="button" value="Send" />
<% Html.EndForm(); %>

<% Html.BeginForm("Cancel", "MyController", FormMethod.Post); %>
<input type="submit" name="button" value="Cancel" />
<% Html.EndForm(); %>

Also, in the case of "Cancel", you are usually just not processing the form and are going to a new URL. In this case you do not need to submit the form at all and just need a link:

<%=Html.ActionLink("Cancel", "List", "MyController") %>