[GIS] How to modify a LYR file using ArcObjects

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I'm creating an Add-in for ArcCatalog using C# that modifies the datasources of layers in a MXD and .LYR files by themselves. I have gotten the MXD code to work but I'm lost with how to modify a .LYR file without the use of IMap. Does anyone have any code suggestions?

To load an MXD and loop and start modifying layers in the TOC was simply something like:

UID pUID = new UIDClass();

            pDoc.Open("C:\\Test\\File1.mxd");

            for (int i = 0; i < pDoc.MapCount; i++)
            {
                pMap = pDoc.get_Map(i);

                UID uid = new UIDClass();
                uid.Value = "{40A9E885-5533-11d0-98BE-00805F7CED21}"; //IFeatureLayer
                IEnumLayer layers = pMap.get_Layers(uid, true);       //Returns all layers

But I'm unsure how to get this process going for standalone .LYR files..

ILayerFile l = new LayerFileClass();
l.Open(fileName);

Best Answer

Do you just need to do "l.Layer"? Hard to say since not sure what\how you do the processing after "IEnumLayer layers = pMap.get_Layers(uid, true);".

One point to note is the .lyr file's Layer could be a group layer so you would need to check and gets its contents (and ensure its not a grouplayer in grouplayer ...), basically some sort of recursive function.

Have said the above, depending upon what version you are on you might look at arcpy.

gis.stackexchange ....change-data-source-path-in-lyr-files-in-arcgis-10

Related Solutions

ArcObjects Custom Layer – Why Custom Layer Is Not Drawing Using ArcObjects

Here's a minimalist custom layer:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using ESRI.ArcGIS.ADF.BaseClasses;
using ESRI.ArcGIS.Geometry;
using ESRI.ArcGIS.Display;
using ESRI.ArcGIS.esriSystem;

namespace MapControlApplication1
{
    class CustLayer2: BaseCustomLayer
    {
        public override void Draw(esriDrawPhase drawPhase, IDisplay Display, ITrackCancel trackCancel)
        {
            System.Diagnostics.Debug.Print("drawing {0} {1}", drawPhase,  Environment.TickCount);
        }
    }
}

I created a new Project and choosing C#>ArcGIS>Extending ArcObjects>Mapcontrol Application, then added a new menuitem on the menu of MainForm with this:

private void testToolStripMenuItem_Click(object sender, EventArgs e)
{
    try
    {
        CustLayer2 layer = new CustLayer2();
        layer.Name = "cust layer2";
        axMapControl1.AddLayer(layer);
    }
    catch (Exception ex)
    {
        MessageBox.Show(this, ex.Message);
    }
}

When I run I see this output as I pan around the map:

drawing esriDPGeography 441416029
drawing esriDPGeography 441422207
drawing esriDPGeography 441433579

[GIS] How to determine if a LYR file has more than one Layer using ArcObjects

Query interface from ILayerFile.Layer to ICompositeLayer to determine whether the layer is a group/composite layer.

If the QI succeded, check ICompositeLayer.Count to see if it has any sublayers.

e.g.:

ILayerFile layerFile = new LayerFileClass();
layerFile.Open(layerFilePath);
ICompositeLayer compositeLayer = layerFile.Layer as ICompositeLayer;
if (compositeLayer != null && compositeLayer.Count > 0)
{
    // do something with the sublayers
}

You can then access a sublayer by its index (probably using a for loop) using the ICompositeLayer.Layer property, which, because it takes an argument should be called as a method in .NET, e.g.: compositeLayer.get_Layer(i).

If you think the layer file might have multiple nested group layers, you would want to write a recursive function to loop through each sublayer and recurse if it is also a composite layer or do something else with it if not.

Best Answer

Related Solutions

ArcObjects Custom Layer – Why Custom Layer Is Not Drawing Using ArcObjects

[GIS] How to determine if a LYR file has more than one Layer using ArcObjects

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