How to change listview checkbox toggle state to THREE state?

[Vincent]

I set the ShowCheckBoxes property of a ListView to true. Now how can I change checkbox state to THREE state instead of two states. I know with a CheckBox you can set IsThreeState = true. I am not able to find this property of the ListView. 

thanks,
Kris...

[Ivan Todorov]

Hi Vincent,

Thank you for contacting us.

Currently, this feature is not supported by RadListView. However, as this sounds like a reasonable functionality, I have logged it to PITS as a feature request and we will implement it in a future release. Here is the link to the PITS item. For the time being, you can enable the ThreeState behavior of RadListView's items by adding a visual style to the indeterminate state of the items in the theme you are using and using the following code to apply it:

public Form1()
{
    InitializeComponent();
    ThemeResolutionService.LoadPackageFile(@"C:\CustomControlDefault.tssp");
    this.radListView1.ThemeName = "CustomControlDefault";
    this.radListView1.VisualItemCreating += new ListViewVisualItemCreatingEventHandler(radListView1_VisualItemCreating);
}

void radListView1_VisualItemCreating(object sender, Telerik.WinControls.UI.ListViewVisualItemCreatingEventArgs e)
{
    e.VisualItem.ToggleElement.IsThreeState = true;
}

I have attached the theme package used in the above snippet along with a screenshot which demonstrates how to add style to the indeterminate state.

Your Telerik points have been updated for your feature request.

I hope you find this useful.

Kind regards,
Ivan Todorov
the Telerik team