Select and highlight features

Question

I have 2 ESRI feature layers on my map; points and polylines. I can select them just fine either by rectangle or polygon. What I am missing is how to highlight (larger size and different color) the selected points and polylines for display. Do I need to create new layers with just the selected features and use a renderer or place a graphic container on the map with those features highlighted? The ultimate goal is to have the selected and highlighted features available for deletion.

Using ArcEngine and ArcSDE. C# .NET.

Thank you.

Answer 1

There are a couple of ways to do this:

1. Select your features and create a new layer. Then you can do whatever you want with them while still keeping the original data. If you want to delete those features at a later time, you can do that too.

2. Create a new field in the attributes of the layers. Something like "SELECT" or whatever makes it clear. Then select your features and use the field calculator to add an indicator (like "YES") to the selected features "SELECT" field. You can now use a definition querry to isolate those features. It will be something like: display only features where [SELECT] = "YES". To get all features on the map, just copy and paste the layer so there is one with the D.Q. and one without.

Hope this helps.

Answer 2

Are you just looking for selection code? (Don't really understand what you are requesting?!) This code will highlight (as an outline) your selection on the target layer using a filter clause ("Key = whatever") in accordance with the passed esriSelectionResultEnum flag:

public static void SelectBy(
    IActiveView view, 
    ILayer2 targetLayer, 
    string filterClause, 
    esriSelectionResultEnum selectionResult
)
{
    IFeatureSelection featureSelection = targetLayer as IFeatureSelection;
    if (featureSelection == null) return;
    IQueryFilter queryFilter = new QueryFilterClass();
    queryFilter.WhereClause = filterClause;
    IColor selectColor = Local.ColorToIColor(System.Drawing.Color.OrangeRed);
    ISimpleFillSymbol fillSymbol = new SimpleFillSymbolClass();
    fillSymbol.Color = selectColor;
    ISimpleLineSymbol outlineSymbol = new SimpleLineSymbolClass();
    outlineSymbol.Color = selectColor;
    outlineSymbol.Width = 2;
    fillSymbol.Outline = outlineSymbol;
    fillSymbol.Style = esriSimpleFillStyle.esriSFSHollow;
    featureSelection.SelectionSymbol = fillSymbol as ISymbol;
    featureSelection.SetSelectionSymbol = true;
    featureSelection.SelectFeatures(queryFilter, selectionResult, false);
    view.PartialRefresh(esriViewDrawPhase.esriViewGeoSelection, view.FocusMap, null);
}

If you know the data this will work. If you need to select by shape that is different.