MVC 4 AjaxBeginForm 用多重按鈕

參考文章：Handling multiple submit buttons on the same form - MVC Razor

一般使用Ajax.BeginForm會搭配Submit button觸發，
要使用多重按鈕
1.必須要指定所有按鈕都有相同的name屬性(name="btn")
2.每個按鈕賦予不同的值(value = "Create" or value = "Update" )
3.在Controller中，除了model的參數外(ModelDto XDto)，
還要加上從View傳到Control 的值，參數的命名必須跟name屬性相同(string btn )
4.利用btn當作條件做判斷

--View-----------------------------------------------------------------------------------------------------

@using (Ajax.BeginForm("Create", "DIM", new AjaxOptions { HttpMethod = "POST", Confirm = "確定要變更?", UpdateTargetId = "ajaxBody" }))
{
    @Html.EditorFor(model => model.id)
    
        
        
    
}

--Controller------------------------------------------------------------------------------------------------
// POST: /DIM/Create

[HttpPost]
public ActionResult Create(ModelDto XDto, string btn)
{        
    if (ModelState.IsValid)
    {
        if (btn == "Create")
        {
            db.ModelDto .Add(XDto);
            db.SaveChanges();
        }
        else
        {
            db.Entry(XDto).State = EntityState.Modified;
            db.SaveChanges();
        }
    }
    return RedirectToAction("List");
}