How do I calculate polygon area with arcobjects?

Question

I'd like to develop an application with ArcEngine that can calculate the area of a polygon.

I wrote the below code to select a polygon in a combobox:

for (int i = 0; i < pmapcontrol2.LayerCount; i++)
{

    Pfeaturelayer = (IFeatureLayer)pmapcontrol2.get_Layer(i);
    if (Pfeaturelayer.FeatureClass.ShapeType == esriGeometryType.esriGeometryPolygon)
    {


        cmbfeaturelayer.Items.Add(pmapcontrol2.get_Layer(i).Name);
    }
}

But I couldn't write code to calculate pfeaturelayer area. I think I should use Ilayer interface and Ilayer use Ifeature to calculate area not ifeaturelayer.

Is there any way to use Ifeature for this application?

Answer 1

Here is a link for some sample code that calculates area of selected polygon feature.

http://edndoc.esri.com/arcobjects/9.2/ComponentHelp/esriGeometry/Area_Example.htm

// The example shows how to get the properties for a selected polygon in
// an ArcMap edit session.
public void showPolygonProperties()
{
    //get editor extension
    UID editorUID = new UIDClass();
    editorUID.Value = "esriEditor.Editor";
    IEditor editor = m_application.FindExtensionByCLSID(editorUID) as IEditor;
    if (editor.SelectionCount != 1)
    {
        System.Windows.Forms.MessageBox.Show("Start Editor and select one polygon");
        return;
    }
    IEnumFeature selectedFeatures = editor.EditSelection;
    IPoint centerPoint = new ESRI.ArcGIS.Geometry.Point();
    IPoint labelPoint = new ESRI.ArcGIS.Geometry.Point();
    IFeature feature = selectedFeatures.Next();
    while (feature != null)
    {
        if (feature.Shape.GeometryType == esriGeometryType.esriGeometryPolygon)
        {
            IArea area = feature.Shape as IArea;
            String message = "+++Polygon.IArea properties...\n" +
            "Area = " + area.Area + "\n" +
            "Center.X = " + area.Centroid.X + "\n" +
            "Center.Y = " + area.Centroid.Y + "\n" +
            "LabelPoint.X = " + area.LabelPoint.X + "\n" +
            "LabelPoint.Y = " + area.LabelPoint.Y;
            area.QueryCentroid(centerPoint);
            area.QueryLabelPoint(labelPoint);
            message = message + "\n" + "+++Polygon.IArea Queries..." + "\n" +
            "Center = " + centerPoint.X + "," + centerPoint.Y + "\n" +
            "Label = " + labelPoint.X + "," + labelPoint.Y;
            System.Windows.Forms.MessageBox.Show(message);
        }
        feature = selectedFeatures.Next();
    }
}