Listview WPF : Add bg color programatically

Question

Hi I am trying to add color to bg of a listview item dynamically while runtime but I get the following exception.

Unable to cast object of type 'RootObject.Controls.ListItem' to type 'System.Windows.Controls.ListViewItem'.

My requirement is to check a condition while clicking a button and if the process is success change the bg to green else red. Here is my WPF code

 <ListView x:Name="ListView" SelectionChanged="List_SelectionChanged" MouseDoubleClick="List_MouseDoubleClick"  SelectionMode="Single"/>

And here is my code behind,

if(RootVal.sendResult == true)
{                       
  foreach (ListViewItem item1 in ListView.Items)
      {
        item1.Background = System.Windows.Media.Brushes.Green;
      }
}

I immediately noticed this : `foreach (ListViewItem item1 in ListView.Items)`. Is your ListView named `ListView`? — Timothy Groote, Jun 16 '17 at 07:11
Obviously `Items` contains collection of `RootObject.Controls.ListItem` rather than `System.Windows.Controls.ListViewItem`. Show where you set `ItemsSource` of the `ListView`. — Maxim, Jun 16 '17 at 07:12
@TimothyGroote The Name is set custom I changed it here thinking it might be confusing. And yes I am populating with custom controls — Sangathamilan Ravichandran, Jun 16 '17 at 07:16
@Maxim Here is the code.. private ObservableList ListOfItems= new ObservableList(); ListView.ItemsSource = ListOfItems; — Sangathamilan Ravichandran, Jun 16 '17 at 07:17
Regardless of what you populated your ListView with, why not just use `foreach (var item1 in ListView.Items)`? C# will take care of the rest. — Keyur PATEL, Jun 16 '17 at 07:17
Take a look at type of the objects in `Items` collection in debugger and say us what do you see. — Maxim, Jun 16 '17 at 07:18
@KeyurPATEL Tried it already.. But this will throw an compile error that object contains no definition for background — Sangathamilan Ravichandran, Jun 16 '17 at 07:20
So why do you expect `ListViewItem` in `Items` if you have collection of `ListItem` there? Title of the question is completely wrong, your problem doesn't related with setting of background. — Maxim, Jun 16 '17 at 07:21
@Sanga Sounds like you need to modify your control `ListItem` to implement the `Background` field. — Keyur PATEL, Jun 16 '17 at 07:24
@Maxim Yes sorry.. got it now...Now Trying to access and set property through Datatemplate binding.. Thanks all.. Have a nice day.. — Sangathamilan Ravichandran, Jun 16 '17 at 07:25

score 1 · Accepted Answer · answered Jun 16 '17 at 07:21

1

The Items property of the ListView does not contain controls, it contains your (view)models. (the ones you set as the ItemsSource)

The proper way of going about this MVVM style would be to bind the background color from the DataTemplate of the ListView to a property of your (view)model.

If you are still looking for a way to set the ListViewItem's background color, take a look at How can I access the ListViewItems of a WPF ListView?

(but be warned, they're not so easy to reach)

answered Jun 16 '17 at 07:21

Timothy Groote

8,614
26
52

Note that `Items` contains view models only if your item presenters created dynamically with `ItemsSource`. You can populate `ListView` by `ListViewItem`'s explicitly and then `Items` will contain collection of `ListViewItem`. – Maxim Jun 16 '17 at 07:28
@Maxim Yes.. Its created dynamically with itemsource... hopefully this works.. Thanks.. – Sangathamilan Ravichandran Jun 16 '17 at 07:31

Listview WPF : Add bg color programatically

1 Answers1