Creating a new layer from query results

Question

Newbie in ArcObjects programming. Using C#. Developing a desktop application.

I need to join 2 tables:

• POI layer which is a Point layer and
• a parcel layer which is a Polygon

Where

POI.HouseNo = Parcel.UNIT_ID

and then create a new Shapefile which has only the 4 fields:

• POIName,
• POIType,
• HouseNo (all from POI layer attributes),
• ParcelName (all from Parcel Layer attributes).

The user selects the POI Layer and the Parcel layer from combo boxes.

Here is the code I have written so far:

IFeatureWorkspace featureWorkspace;
IQueryDef queryDef = featureWorkspace.CreateQueryDef();
queryDef.Tables = cboPOI.Text + "," + cboParcel.Text;
queryDef.SubFields = cboPOI.Text + ".Name," + cboPOI.Text + ".Type," + cboPOI.Text +".HouseNo," + cboParcel.Text + ".ParcelName";
queryDef.WhereClause = cboPOI.Text + ".HouseNo =" + cboParcel.Text+ ".UNIT_ID";

Hope I'm on the right track. Now I need to run this query and get the output to a new Shapefile. How can I do this?

please help.

Answer 1

The AO-API has got an example. This would mean that you would have to extent your code by the following lines:

IFeatureDataset featureDataset = featureWorkspace.OpenFeatureQuery("MyJoin", queryDef);
IFeatureClassContainer featureClassContainer = (IFeatureClassContainer)featureDataset;
IFeatureClass featureClass = featureClassContainer.get_ClassByName("MyJoin");

And just assign that feture class to a feature layer. Assuming you really want to create a new shapefile in the filesystem, you can export the created feature class with a geoprocessor like FeatureClassToShapefile.