How does @Html.BeginForm() work? and search result in Microsoft ASP.Net MVC 5 tutorial?

Question

I am working on MVC 5 Asp.Net and following this tutorial. I am wondering how the heck does this fetch the result when I click the Filter button?

There comes a point where this code is added in Movie/view/Index.cshtml

@using (Html.BeginForm())
{    
     <p> Title: @Html.TextBox("SearchString") <br />   
     <input type="submit" value="Filter" /></p> 
} 

Now as far as I know, it creates a textbox and a button on screen. But how is this button calling the search(index) function and passing the value of textbox in the function, I could not get this.

Answer 1

It's not a stupid question. @html.BeginForm() works like this. It has some parameters you could add to it like Action Controller FormType htmlAttributes. The way it works is that if you leave it empty it will look for a post action with the same name that on the page you are now, for example if you are in on the login page, it will look for a login post action. I always write what action and controller I want it to access.

@Html.BeginForm("AddUser", "Admin", FormMethod.Post, new { @class = "my_form"}) {

}

So your post action should accept parameters that your form contains, and that can be a Model ie a Product, ViewModel or single string parameters. In your case with the search your action should look like

[HttpPost]
public ActionResult Search(string SearchString) 
{
   //do something here
}

Please note here, for the search string to be passed into the method. The name of the <input> has to be the same as the parameter your action takes. So our form should be like this

@using (Html.BeginForm("Search", "YOUR CONTROLLER", FormMethod.Post)){    
     <p> Title: @Html.TextBox("SearchString") <br />   
     <input type="submit" value="Filter" /></p> 
} 

Hope this brings clarity.