SelectBox.cs

This example demonstrates how to manually select shapes and to show information about the their relative area. The shapes area selected by mouse dragging. Chart is update automatically. Here is a screenshot with the results of the code execution.

SelectBox.png
using System.IO;
using System.Windows.Forms;
using AxMapWinGIS;
using MapWinGIS;
namespace Examples
{
public partial class MapExamples
{
// <summary>
// Adds the layers and register event handler.
// </summary>
public void SelectBox(AxMap axMap1, string dataPath)
{
axMap1.Projection = tkMapProjection.PROJECTION_GOOGLE_MERCATOR;
string filename = dataPath + "landuse.shp";
if (!File.Exists(filename))
{
MessageBox.Show("Couldn't file the file: " + filename);
return;
}
Shapefile sf = new Shapefile();
sf.Open(filename, null);
if (!sf.StartEditingShapes(true, null))
{
MessageBox.Show("Failed to start edit mode: " + sf.Table.ErrorMsg[sf.LastErrorCode]);
}
else
{
sf.UseQTree = true;
sf.Labels.Generate("[Name]", tkLabelPositioning.lpCentroid, false);
axMap1.AddLayer(sf, true);
axMap1.SendSelectBoxFinal = true;
MapEvents.SelectBoxFinal += AxMap1SelectBoxFinal; // change MapEvents to axMap1
axMap1.MapUnits = tkUnitsOfMeasure.umMeters;
axMap1.CurrentScale = 50000;
axMap1.CursorMode = tkCursorMode.cmSelection;
}
}
// <summary>
// Performs selection, updates charts
// </summary>
void AxMap1SelectBoxFinal(object sender, _DMapEvents_SelectBoxFinalEvent e)
{
// it's assumed here that the layer we want to edit is the first 1 (with 0 index)
int layerHandle = axMap1.get_LayerHandle(0);
Shapefile sf = axMap1.get_Shapefile(layerHandle);
if (sf != null)
{
double left = 0.0;
double top = 0.0;
double bottom = 0.0;
double right = 0.0;
axMap1.PixelToProj(e.left, e.top, ref left, ref top);
axMap1.PixelToProj(e.right, e.bottom, ref right, ref bottom);
object result = null;
var ext = new Extents();
ext.SetBounds(left, bottom, 0.0, right, top, 0.0);
sf.SelectNone();
if (sf.SelectShapes(ext, 0.0, SelectMode.INTERSECTION, ref result))
{
int[] shapes = result as int[];
if (shapes == null) return;
for (int i = 0; i < shapes.Length; i++)
{
sf.set_ShapeSelected(shapes[i], true);
}
}
axMap1.Redraw();
}
}
}
}