C#•3y ago

Remove list element

AddTabGroupChildren(Config.KpiSelection.TabHierarchy.TabBase);
private void AddTabGroupChildren(List<XmlTabBase> members)
{
    members = members
        .OrderBy(p => p.Order)
        .ToList();

    var children = members.OfType<XmlTabGroup>().ToLookup(group => group.GroupId);
    foreach (var member in members.OfType<XmlTabGroup>().ToList())
    {
        member.TabBase.AddRange(new List<XmlTabGroup>(children[member.Order].ToList()));
        member.TabBase = member.TabBase.OrderBy(p => p.Order).ToList();
        if (member.GroupId != 0) members.RemoveAt(members.FindIndex(p => p.Order == member.Order));
    }
}

AddTabGroupChildren(Config.KpiSelection.TabHierarchy.TabBase);
private void AddTabGroupChildren(List<XmlTabBase> members)
{
    members = members
        .OrderBy(p => p.Order)
        .ToList();

    var children = members.OfType<XmlTabGroup>().ToLookup(group => group.GroupId);
    foreach (var member in members.OfType<XmlTabGroup>().ToList())
    {
        member.TabBase.AddRange(new List<XmlTabGroup>(children[member.Order].ToList()));
        member.TabBase = member.TabBase.OrderBy(p => p.Order).ToList();
        if (member.GroupId != 0) members.RemoveAt(members.FindIndex(p => p.Order == member.Order));
    }
}

I have a method which takes a flat list and generates a tree from it. At the end I remove the elements from the list which have been added as a child. This is the part which isn't working anymore and I don't understand why. Meaning when I look at members inside the method, the list at the end is correct, but the actual property still has the deleted elements. The added children are correct though.

4 Replies

mikernet•3y ago

You're not removing from the list that is passed into the method You're removing from the new list you created inside the method

    members = members
        .OrderBy(p => p.Order)
        .ToList();

    members = members
        .OrderBy(p => p.Order)
        .ToList();

This creates a new list, so the list you passed into this method won't be affected.

Iceman228OP•3y ago

Just figured that out as well. Thanks though.

mikernet•3y ago

Is there a reason you're doing members.RemoveAt(members.FindIndex(p => p.Order == member.Order)); instead of members.Remove(member)?

Iceman228OP•3y ago

I am trying to think of one and don't find it. I will test it without.

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Remove list element