Remove .sr lock on shapefile after removing layer from map using ArcObjects and C#

Question

I am having difficulty figuring out how to remove .sr lock files from shapefiles using ArcObjects and C# after removing the associated layer from the map. I notice that using the straight UI in ArcMap that removing a layer will remove the lock file, but I cannot get this to happen programmatically. I have tried everything that I can think of, including calling Marshal.FinalReleaseComObject on all variables. The following is some paired down test code that simply loads a layer into the map and then immediately removes it. This should remove the lock files, but it does not. Am I missing something?

// Loop through the selected shapefiles and load into the map
pGxObjects.Reset();

while ((pGxDataset = (IGxDataset)pGxObjects.Next()) != null)
{
    IFeatureLayer pFeatLayer = new FeatureLayer();
    pFeatLayer.FeatureClass = (IFeatureClass)pGxDataset.Dataset;
    pFeatLayer.Name = pFeatLayer.FeatureClass.AliasName;
    pMxDoc.FocusMap.AddLayer(pFeatLayer);

    // Do something with the layer

    pMxDoc.FocusMap.DeleteLayer(pFeatLayer);
    Marshal.FinalReleaseComObject(pFeatLayer);
    Marshal.FinalReleaseComObject(pGxDataset);
}

Marshal.FinalReleaseComObject(pGxObjects);
GC.Collect();
GC.WaitForPendingFinalizers();

Answer 1

This is an issue I've never solved in a satisfactory way. The only way in ArcMap I can reliably remove locks is to collapse all Catalog folders and right click > refresh them AND to open a new map in ArcMap. However, in code there's an ugly work around.

Each shapefile is several files all with the same name and a different extension. So when using a shapefile you can first copy all the files, bar the .sr.lock file, to a new location or to the same location with a different name, then work with that shapefile.

ArcMap does not lock shapefile's files. That means if you want to delete or replace the shapefile you can delete or overwrite all the shapefile's files with the exception of the lock files. The lock files should be deleted when ArcMap closes.

So putting it together you can copy the shapefile, do whatever you need to it, and then replace the original, and then refresh the ArcMap layer.