Editing using a custom form
MainForm.cs
// Copyright 2012 ESRI
// 
// All rights reserved under the copyright laws of the United States
// and applicable international laws, treaties, and conventions.
// 
// You may freely redistribute and use this sample code, with or
// without modification, provided you include the original copyright
// notice and use restrictions.
// 
// See the use restrictions.
// 

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.IO;
using System.Runtime.InteropServices;

using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Controls;
using ESRI.ArcGIS.ADF;
using ESRI.ArcGIS.SystemUI;
using ESRI.ArcGIS.DataSourcesFile;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS.Display;

namespace EditingUsingCustomForm
{
    public sealed partial class MainForm : Form
    {
        #region private members
        private IMapControl3 m_mapControl = null;
        #endregion

        #region class constructor
        public MainForm()
        {
            InitializeComponent();
        }
        #endregion

        private void MainForm_Load(object sender, EventArgs e)
        {        
            m_mapControl = (IMapControl3) axMapControl1.Object;

            //relative file path to the sample data from EXE location
            string filePath = @"..\..\..\data\USAMajorHighways";
 
            //Add Lakes layer
            IWorkspaceFactory workspaceFactory = new ShapefileWorkspaceFactoryClass();
            IFeatureWorkspace workspace = (IFeatureWorkspace)workspaceFactory.OpenFromFile(filePath, axMapControl1.hWnd);
            IFeatureLayer featureLayer = new FeatureLayerClass();
            featureLayer.Name = "Lakes";
            featureLayer.Visible = true;
            featureLayer.FeatureClass = workspace.OpenFeatureClass("us_lakes");

            #region create a SimplerRenderer
            IRgbColor color = new RgbColorClass();
            color.Red = 190;
            color.Green = 232;
            color.Blue = 255;

            ISimpleFillSymbol sym = new SimpleFillSymbolClass();
            sym.Color = color;

            ISimpleRenderer renderer = new SimpleRendererClass();
            renderer.Symbol = sym as ISymbol;
            #endregion

            ((IGeoFeatureLayer)featureLayer).Renderer = renderer as IFeatureRenderer;
            axMapControl1.Map.AddLayer((ILayer)featureLayer);

            //Add Highways layer
            featureLayer = new FeatureLayerClass();
            featureLayer.Name = "Highways";
            featureLayer.Visible = true;
            featureLayer.FeatureClass = workspace.OpenFeatureClass("usa_major_highways");
            axMapControl1.Map.AddLayer((ILayer)featureLayer);

            //******** Important *************
            //store a reference to this form (Mainform) using the EditHelper class
            EditHelper.TheMainForm = this;
            EditHelper.IsEditorFormOpen = false;

            //add the EditCmd command to the toolbar
            axEditorToolbar.AddItem("esriControls.ControlsOpenDocCommand", 0, -1, false, 0, esriCommandStyles.esriCommandStyleIconOnly);
            axEditorToolbar.AddItem("esriControls.ControlsSaveAsDocCommand", 0, -1, false, 0, esriCommandStyles.esriCommandStyleIconOnly);
            axEditorToolbar.AddItem("esriControls.ControlsAddDataCommand", 0, -1, false, 0, esriCommandStyles.esriCommandStyleIconOnly);
            axEditorToolbar.AddItem(new EditCmd(), 0, -1, false, 0, esriCommandStyles.esriCommandStyleIconOnly);
             
        }

        private void MainForm_Shown(object sender, EventArgs e)
        {
            //Warn users if the ArcGIS Engine samples used by this application have not been compiled
            ArrayList checkList = new ArrayList();
            checkList.Add("ReshapePolylineEditTask_CS.ReshapePolylineEditTask");
            checkList.Add("VertexCommands_CS.UsingOutOfBoxVertexCommands");

            Type t = null;
            bool success = true;

            foreach (string item in checkList)
            {
                t = Type.GetTypeFromProgID(item);

                if (t == null)
                {
                    success = false;
                    break;
                }
            }

            if (!success)
                MessageBox.Show("Editing will not function correctly until the C# ReshapePolylineEditTask and VertexCommands samples have been compiled. More information can be found in the 'How to use' section for this sample.",
                    "Warning",MessageBoxButtons.OK,MessageBoxIcon.Warning);
            
        }


        #region public properties

        // Returns the MapControl
        public IMapControl3 MapControl
        {
            get { return m_mapControl; }
        }

        #endregion

       
        




    }
}