Is there a way to do multiselect in ObjectListView without the Ctrl key pressed?

Question

I set the FullRowSelect and MultiSelect property to true in the ObjectListView component, but I still have to select multiple rows by pressing the Ctrl key. So, Is there a way to do multiselect without the Ctrl or shift key pressed?

Answer 1

I think I have a working solution. The model objects in this example are of type "Item". For some explanations see code comments.

// We require a list to remember which items should stay selected
private List<Item> _MultiSelectList;

public Form1() {
    // <other stuff>
    _MultiSelectList = new List<Item>();
}

// use this event to check which item has been clicked
private void objectListView1_MouseClick(object sender, MouseEventArgs e) {
    objectListView1.BeginUpdate();

    // any item clicked?
    if (objectListView1.MouseMoveHitTest.Item != null) {
        var item = objectListView1.MouseMoveHitTest.Item.RowObject as Item;

        // model object of expected type available?
        if (item != null) {
            // add or remove item from list to effectively toggle selection
            if (_MultiSelectList.Contains(item)) {
                _MultiSelectList.Remove(item);
            } else {
                _MultiSelectList.Add(item);
            }
        }
    }

    // select all desired items
    objectListView1.SelectObjects(_MultiSelectList);
    objectListView1.EndUpdate();
}

// optional: to prevent flickering from the native item selection change, we freeze the OLV contents during the mouse click
private void objectListView1_MouseDown(object sender, MouseEventArgs e) {
    objectListView1.Freeze();
}

private void objectListView1_MouseUp(object sender, MouseEventArgs e) {
    objectListView1.Unfreeze();
}