检查部分视图是否在ASP.Net MVC中返回Null或为空

Question

I have a View with a Partial View in it. Both the View and the Partial View have their own View Model (VM). In the Views VM I create a property of the Partial Views VM and then I pass that property into the RenderAction for the Partial view.

@{ Html.RenderAction("PartialItem", "_PViewItem", Model.PV_Page_Item); }

In some cases the Partial View will have data in it and others it will be null. There are several other bits of HTML in the parent View that I only want to show if the Partial View has data in it.

What I need to know is how can I tell if the Partial View returns data or is Null?

Answer 1

You can put an IF around the RenderAction. As others mentioned, it's too late if the partial is already being loaded to stop showing it.

Something like (the if happens on server side)

if (Model.PV_Page_Item != null)
{
@{ Html.RenderAction("PartialItem", "_PViewItem", Model.PV_Page_Item); }
}

Answer 2

In your action you could do something like .

{
var result = Repository.GetData();

          if (result.Any())
            {
                return PartialView("_yourPartialView", result);
            }
            return null;
}

And in your client code add a null check condition and display result accordingly.

Answer 3

I would not do it this way. I would rather return the partial view irrespective if there is data in it or not. I am not sure what your partial view looks like, but rather do a check in the partial view on the item, if the item does not contain data then do not display the HTML in the partial view.

Let us assume I have user data in my view coming from a view model , and a list of that user's addresses that I want to send to the partial view. Then I would have something like the code below. UserAddresses is the name of the partial view that I want to pass data to:

@Html.Partial("UserAddresses", Model.Addresses)

So in the partial view I would just do the following:

@if (Model.Count > 0)
{
     foreach (var address in Model)
     {
          <div>@address.Line1</div>
          <div>@address.Line2</div>
          <br />
     }
}

So there is no real need to check for a null partial view, just do not display any HTML if no data is passed through.