Iterate through TOC elements in ArcGis Server 9.3

Question

I'm developing website with a custom tool in ArcGis Server 9.3 using Visual Studio 2008 and the ADF components, the thing is that when I click on my custom tool it calls a class, this class needs to check each layer available to see if it is enabled and visible (this properties changes when you zoom out or zoom in), does anyone knows how to accomplish this? Thanks.

Answer 1

IMap:Layers and IEnumLayer http://edndoc.esri.com/arcobjects/9.1/componenthelp/esricarto/IMap_Layers.htm

Answer 2

I've used this VB.net code to do tasks similar to what you are asking. This is shortened from memory so bear with me.

' Create layer enumerator
' Use IHookHelper focus map (or other reference to an IMap)
Dim layerEnumerator As ArcGIS.Carto.IEnumLayer
layerEnumerator = HookHelper.FocusMap.Layers()
layerEnumerator.Reset()

' Loop through layers
Dim layer As ArcGIS.Carto.ILayer
layer = layerEnumerator.Next
Do While Not layer Is Nothing

     MsgBox("Layer: " & layer.Name)

     ' Check to see if layer is valid
     If layer.Valid Then
          ' Do something...
     End If

     ' Check to see if layer is visible
     If layer.Visible Then
         ' Do something...
     End If

     ' Get the next layer in the enumerator
     layer = layerEnumerator.Next

Loop

Update: If instead you are using the .Net Web ADF you might want to take a look at the MapFunctionality class here. I've not used it but the GetLayerInfo method appears to provide the information you need.