Model binder in Razor View

I have a Model here

```
[Serializable]
public class StaffInfoModel
{
[Display(Name = "Work Number")]
public string workNum { get; set; }
}
```

Then In my Index view, I have a input tag to bind `workNum` property

```
@model StaffInfoModel
@{
ViewData["Title"] = "Home Page";
}

Here is my controller code:

```
public IActionResult Index()
{
return View();
}

public IActionResult Query()
{
return View();
}

[HttpPost]
public IActionResult Query(QueryInfoModel model)
{
StaffInfoModel staff = new StaffInfoModel();
staff.workNum = "1010101010";

Console.WriteLine(staff.workNum);

return View("Index", staff);
}

public IActionResult Privacy()
{
StaffInfoModel staff = new StaffInfoModel();
staff.workNum = "1010101010";

return View("Index", staff);
}
```

And here is my query page:

```
@model QueryInfoModel
@{
ViewData["Title"] = "Query Page";
}

The problem is when i access privacy, It will return index view with data, And the data can be show successfully. Then when I access query page and click button, the code will access query post action then return index view with data, But the data will not show in index page. Only i add `value="@Model.workNum"` manually in input tag can show the data normally, I don't know why the same code cause different situation.