Creating report from selected features in ArcMap using AddIn and C#?

Question

I am new to ArcGIS and I am trying to create an Add-In button which can

1. figure out which polygons are selected and
2. query the selected polygons to generate a report on the underlying metadata (similar to the Identify tool).

I had a look at this article, which helped with finding the selected feature layer, but I haven't been able to progress much further.

At the moment all I have is a one-liner. Here is some pseudo code of what I would like to do:

var featureLayer = ArcMap.Document.CurrentContentsView.SelectedItem as IFeatureLayer;
var selectedFeatures = featureLayer.SelectedFeatures;
// A list to contain the info available in Identify tool (not sure what this is called)
var featuresAttributes = new List<FeatureAttributes>();
// For each selected polygon
foreach(var feature in selectedFeatures)
 featuresAttributes.Add(feature.Attributes);
// Go off and generate some report based on the selected polygon attributes
MyReportGenerator.CreateReport(featuresAttributes); 

• artwork21: @Andre, What type of info are you wanting to generate from your report, statistics, list of selected features + statistics? Also, do you have a desired file type for your report, eg. dbf, xls, rdf, txt...?
• André Haupt: In this instance all values are numerical, thus any aggregate can be used. In my clients case, each polygon represent an urban area with some underlying data/attributes such as % commercial, % residential, etc. We have yet to decide on the final report type, but it could be any arbitrary report.

Answer 1

You can use dictionaries for this type of thing. There are more memory efficient ways of doing this (by just storing field names once), but this might get you started.

public void TestGetSelection()
{
 var dict = GetSelection(ArcMap.Document.FocusMap.get_Layer(0) as IFeatureLayer);
 foreach (KeyValuePair<int, Dictionary<string, object>> kvp in dict)
 {
 Debug.Print("{0} {1}", kvp.Key, kvp.Value["State_Name"]);
 }
}
public static Dictionary<int, Dictionary<string, object>> GetSelection(IFeatureLayer fLayer)
{
 // return a dictionary containing one dictionaries for each selected
 // feature where the contained dictionary is keyed by the field name
 var dict = new Dictionary<int, Dictionary<string, object>>();
 ICursor cur = null;
 try
 {
 ((IFeatureSelection)fLayer).SelectionSet.Search(null, false, out cur);
 IRow row;
 while ((row = cur.NextRow()) != null)
 {
 dict.Add(row.OID, RowToDict(row));
 }
 }
 catch
 {
 throw;
 }
 finally
 {
 if (cur != null)
 System.Runtime.InteropServices.Marshal.FinalReleaseComObject(cur);
 }
 return dict;
}
public static Dictionary<string, object> RowToDict(IRow row)
{
 var dict = new Dictionary<string, object>(StringComparer.InvariantCultureIgnoreCase);
 for (int i = 0; i < row.Fields.FieldCount; i++)
 {
 var fld = row.Fields.get_Field(i);
 if (row.get_Value(i) is DBNull)
 {
 // todo: maybe special treatment of nulls here ...
 }
 if(fld.Type != esriFieldType.esriFieldTypeGeometry)
 dict.Add(fld.Name, row.get_Value(i));
 }
 return dict;
}

Answer 2

One option would be to use the report writer, create report command (ArcMap Command), see code below:

 public void ExecuteCmd2()
{
 try {
 UID pUID = new UID();
 ICommandItem pCmdItem = default(ICommandItem);
 // Use the GUID of the Save command
 pUID.Value = "{CDC6F22A-7DD1-490F-8FDE-4357C621BBDF}";
 // or you can use the ProgID
 // pUID.Value = "ESRI.ArcGIS.ReportWriter.CreateReportCommand"
 pUID.SubType = 3;
 pCmdItem = m_App.Document.CommandBars.Find(pUID);
 pCmdItem.Execute();
 } catch (Exception ex) {
 MessageBox.Show("Caught an unspecified error in the calling code: " + System.Environment.NewLine + ex.ToString());
 }
}

There is an option within one of the dialogs to narrow the report to only selected features. Also, in ArcGIS 10.1 it looks like ESRI may have some reporting functions in python.

http://forums.arcgis.com/threads/42876-Creating-Report-with-Python-in-ArcGIS-10

• Nathanus: What does Constants.vbCrLf call?
• artwork21: @Nathanus, Thanks I updated "Constants.vbCrLf" to "System.Environment.NewLine".
• Nathanus: Oh, I get it, Carriage Return / Line Feed.