How do I reach a layer inside a GroupLayer?

Question

I am having problems in ArcObjects. I am struggling to get to the individual (feature-)layers inside a GroupLayer. Does anyone know how to do that ?

Answer 1

Try this:

public List<ILayer> GetLayers(string groupLayerName)
{

    ICompositeLayer compositeLayer = GetGroupLayer(groupLayerName);
    List<ILayer> layers = new List<ILayer>();

    if (compositeLayer != null)
    {
        for (int j = 0; j < compositeLayer.Count; j++)
        {
            layers.Add(new Layer(compositeLayer.Layer[j]));
        }
    }
    return layers;
}

ICompositeLayer GetGroupLayer(string groupLayerName)
{
     var mapLayers = _map.Layers;
     for (var layer = mapLayers.Next(); layer != null; layer = mapLayers.Next())
     {
            var comLayer = layer as ICompositeLayer;
            var groupLayer = layer as IGroupLayer;
            if ((comLayer != null) && (groupLayer != null) && (layer.Name.Equals(groupLayerName)))
                return groupLayer;
     }
}

Answer 2

Cast the group layer to ICompositeLayer which allows you to access the individual sublayers.