[求助] 用TreeView显示图层名称

请教各位:

本人想在VB中用TreeView控件实现MapControl中地图图层的显示,代码如下:

Dim mLayer As ILayer
Dim parNode As Node
Dim mMap As IMap
Set mMap = MapControl1.Map

TreeView1.Nodes.Clear

Dim x As Long
x = mMap.LayerCount
Dim n As Integer
n = CInt(x)

For i = 1 To n Step 1
 Set mLayer = mMap.Layer(i)
 Set parNode = TreeView1.Nodes.Add(, , , mLayer.Name)
Next i
 parNode.EnsureVisible

End Sub

运行时出现"无效的过程调用或参数"出错提示.

请问各位是怎么回事?如何修改?可否指点一二,非常感谢!

key不是可选的吗?

回复楼上,问题搞定,修改代码如下:

Dim mLayer As ILayer
Dim parNode As Node

TreeView1.Nodes.Clear

dim i as Integer

For i = 0 To Mapcontrol1.LayerCount-1 Step 1
 Set mLayer = Mapcontrol1.Layer(i)
 Set parNode = TreeView1.Nodes.Add(, , , mLayer.Name)
Next i
 parNode.EnsureVisible

End Sub