Displaying MapTips in the MapControl
MapTips.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.Windows.Forms;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.SystemUI;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.Geodatabase;
using ESRI.ArcGIS;


namespace MapTips
{
  public class Form1 : System.Windows.Forms.Form
  {
    public System.Windows.Forms.CheckBox chkShowTips;
    public System.Windows.Forms.Button cmdLoadData;
    public System.Windows.Forms.ComboBox cboDataField;
    public System.Windows.Forms.ComboBox cboDataLayer;
    public System.Windows.Forms.Label Label2;
    public System.Windows.Forms.Label Label1;
    public System.Windows.Forms.Button cmdFullExtent;
    public System.Windows.Forms.Label Label3;
        private System.Windows.Forms.OpenFileDialog openFileDialog1;
    private ESRI.ArcGIS.Controls.AxMapControl axMapControl1;
    private ESRI.ArcGIS.Controls.AxLicenseControl axLicenseControl1;
        internal CheckBox chkTransparent;
    private System.ComponentModel.IContainer components;

    public Form1()
    {
      //
      // Required for Windows Form Designer support
      //
      InitializeComponent();

      //
      // TODO: Add any constructor code after InitializeComponent call
      //
    }

    protected override void Dispose( bool disposing )
    {
            //Release COM objects
            ESRI.ArcGIS.ADF.COMSupport.AOUninitialize.Shutdown();
      if( disposing )
      {
        if (components != null) 
        {
          components.Dispose();
        }
      }
      base.Dispose( disposing );
    }

    #region Windows Form Designer generated code
    /// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
            System.ComponentModel.ComponentResourceManager resources = new System.ComponentModel.ComponentResourceManager(typeof(Form1));
            this.chkShowTips = new System.Windows.Forms.CheckBox();
            this.cmdLoadData = new System.Windows.Forms.Button();
            this.cboDataField = new System.Windows.Forms.ComboBox();
            this.cboDataLayer = new System.Windows.Forms.ComboBox();
            this.Label2 = new System.Windows.Forms.Label();
            this.Label1 = new System.Windows.Forms.Label();
            this.cmdFullExtent = new System.Windows.Forms.Button();
            this.Label3 = new System.Windows.Forms.Label();
            this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();
            this.axMapControl1 = new ESRI.ArcGIS.Controls.AxMapControl();
            this.axLicenseControl1 = new ESRI.ArcGIS.Controls.AxLicenseControl();
            this.chkTransparent = new System.Windows.Forms.CheckBox();
            ((System.ComponentModel.ISupportInitialize)(this.axMapControl1)).BeginInit();
            ((System.ComponentModel.ISupportInitialize)(this.axLicenseControl1)).BeginInit();
            this.SuspendLayout();
            // 
            // chkShowTips
            // 
            this.chkShowTips.BackColor = System.Drawing.SystemColors.Control;
            this.chkShowTips.Cursor = System.Windows.Forms.Cursors.Default;
            this.chkShowTips.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.chkShowTips.ForeColor = System.Drawing.SystemColors.ControlText;
            this.chkShowTips.Location = new System.Drawing.Point(8, 40);
            this.chkShowTips.Name = "chkShowTips";
            this.chkShowTips.RightToLeft = System.Windows.Forms.RightToLeft.No;
            this.chkShowTips.Size = new System.Drawing.Size(129, 25);
            this.chkShowTips.TabIndex = 10;
            this.chkShowTips.Text = "Show Map Tips";
            this.chkShowTips.UseVisualStyleBackColor = false;
            this.chkShowTips.CheckedChanged += new System.EventHandler(this.chkShowTips_CheckedChanged);
            this.chkShowTips.CheckStateChanged += new System.EventHandler(this.chkShowTips_CheckStateChanged);
            // 
            // cmdLoadData
            // 
            this.cmdLoadData.BackColor = System.Drawing.SystemColors.Control;
            this.cmdLoadData.Cursor = System.Windows.Forms.Cursors.Default;
            this.cmdLoadData.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.cmdLoadData.ForeColor = System.Drawing.SystemColors.ControlText;
            this.cmdLoadData.Location = new System.Drawing.Point(8, 8);
            this.cmdLoadData.Name = "cmdLoadData";
            this.cmdLoadData.RightToLeft = System.Windows.Forms.RightToLeft.No;
            this.cmdLoadData.Size = new System.Drawing.Size(113, 25);
            this.cmdLoadData.TabIndex = 9;
            this.cmdLoadData.Text = "Load Document...";
            this.cmdLoadData.UseVisualStyleBackColor = false;
            this.cmdLoadData.Click += new System.EventHandler(this.cmdLoadData_Click);
            // 
            // cboDataField
            // 
            this.cboDataField.BackColor = System.Drawing.SystemColors.Window;
            this.cboDataField.Cursor = System.Windows.Forms.Cursors.Default;
            this.cboDataField.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.cboDataField.ForeColor = System.Drawing.SystemColors.WindowText;
            this.cboDataField.Location = new System.Drawing.Point(176, 40);
            this.cboDataField.Name = "cboDataField";
            this.cboDataField.RightToLeft = System.Windows.Forms.RightToLeft.No;
            this.cboDataField.Size = new System.Drawing.Size(161, 22);
            this.cboDataField.TabIndex = 8;
            this.cboDataField.SelectedIndexChanged += new System.EventHandler(this.cboDataField_SelectedIndexChanged);
            // 
            // cboDataLayer
            // 
            this.cboDataLayer.BackColor = System.Drawing.SystemColors.Window;
            this.cboDataLayer.Cursor = System.Windows.Forms.Cursors.Default;
            this.cboDataLayer.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.cboDataLayer.ForeColor = System.Drawing.SystemColors.WindowText;
            this.cboDataLayer.Location = new System.Drawing.Point(176, 16);
            this.cboDataLayer.Name = "cboDataLayer";
            this.cboDataLayer.RightToLeft = System.Windows.Forms.RightToLeft.No;
            this.cboDataLayer.Size = new System.Drawing.Size(161, 22);
            this.cboDataLayer.TabIndex = 7;
            this.cboDataLayer.SelectedIndexChanged += new System.EventHandler(this.cboDataLayer_SelectedIndexChanged);
            // 
            // Label2
            // 
            this.Label2.BackColor = System.Drawing.SystemColors.Control;
            this.Label2.Cursor = System.Windows.Forms.Cursors.Default;
            this.Label2.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.Label2.ForeColor = System.Drawing.SystemColors.ControlText;
            this.Label2.Location = new System.Drawing.Point(136, 40);
            this.Label2.Name = "Label2";
            this.Label2.RightToLeft = System.Windows.Forms.RightToLeft.No;
            this.Label2.Size = new System.Drawing.Size(33, 17);
            this.Label2.TabIndex = 12;
            this.Label2.Text = "Fields:";
            // 
            // Label1
            // 
            this.Label1.BackColor = System.Drawing.SystemColors.Control;
            this.Label1.Cursor = System.Windows.Forms.Cursors.Default;
            this.Label1.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.Label1.ForeColor = System.Drawing.SystemColors.ControlText;
            this.Label1.Location = new System.Drawing.Point(136, 16);
            this.Label1.Name = "Label1";
            this.Label1.RightToLeft = System.Windows.Forms.RightToLeft.No;
            this.Label1.Size = new System.Drawing.Size(41, 17);
            this.Label1.TabIndex = 11;
            this.Label1.Text = "Layers:";
            // 
            // cmdFullExtent
            // 
            this.cmdFullExtent.BackColor = System.Drawing.SystemColors.Control;
            this.cmdFullExtent.Cursor = System.Windows.Forms.Cursors.Default;
            this.cmdFullExtent.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.cmdFullExtent.ForeColor = System.Drawing.SystemColors.ControlText;
            this.cmdFullExtent.Location = new System.Drawing.Point(224, 365);
            this.cmdFullExtent.Name = "cmdFullExtent";
            this.cmdFullExtent.RightToLeft = System.Windows.Forms.RightToLeft.No;
            this.cmdFullExtent.Size = new System.Drawing.Size(113, 25);
            this.cmdFullExtent.TabIndex = 13;
            this.cmdFullExtent.Text = "Zoom to Full Extent";
            this.cmdFullExtent.UseVisualStyleBackColor = false;
            this.cmdFullExtent.Click += new System.EventHandler(this.cmdFullExtent_Click);
            // 
            // Label3
            // 
            this.Label3.BackColor = System.Drawing.SystemColors.Control;
            this.Label3.Cursor = System.Windows.Forms.Cursors.Default;
            this.Label3.Font = new System.Drawing.Font("Arial", 8F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.Label3.ForeColor = System.Drawing.SystemColors.ControlText;
            this.Label3.Location = new System.Drawing.Point(8, 373);
            this.Label3.Name = "Label3";
            this.Label3.RightToLeft = System.Windows.Forms.RightToLeft.No;
            this.Label3.Size = new System.Drawing.Size(209, 17);
            this.Label3.TabIndex = 14;
            this.Label3.Text = "Left mouse button to zoomin, right to pan";
            // 
            // axMapControl1
            // 
            this.axMapControl1.Location = new System.Drawing.Point(8, 88);
            this.axMapControl1.Name = "axMapControl1";
            this.axMapControl1.OcxState = ((System.Windows.Forms.AxHost.State)(resources.GetObject("axMapControl1.OcxState")));
            this.axMapControl1.Size = new System.Drawing.Size(328, 272);
            this.axMapControl1.TabIndex = 15;
            this.axMapControl1.OnMouseDown += new ESRI.ArcGIS.Controls.IMapControlEvents2_Ax_OnMouseDownEventHandler(this.axMapControl1_OnMouseDown);
            // 
            // axLicenseControl1
            // 
            this.axLicenseControl1.Enabled = true;
            this.axLicenseControl1.Location = new System.Drawing.Point(300, 68);
            this.axLicenseControl1.Name = "axLicenseControl1";
            this.axLicenseControl1.OcxState = ((System.Windows.Forms.AxHost.State)(resources.GetObject("axLicenseControl1.OcxState")));
            this.axLicenseControl1.Size = new System.Drawing.Size(32, 32);
            this.axLicenseControl1.TabIndex = 16;
            // 
            // chkTransparent
            // 
            this.chkTransparent.AutoSize = true;
            this.chkTransparent.Location = new System.Drawing.Point(8, 65);
            this.chkTransparent.Name = "chkTransparent";
            this.chkTransparent.Size = new System.Drawing.Size(106, 17);
            this.chkTransparent.TabIndex = 17;
            this.chkTransparent.Text = "Transparent Tips";
            this.chkTransparent.UseVisualStyleBackColor = true;
            this.chkTransparent.CheckedChanged += new System.EventHandler(this.chkTransparent_CheckedChanged);
            // 
            // Form1
            // 
            this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
            this.ClientSize = new System.Drawing.Size(344, 400);
            this.Controls.Add(this.chkTransparent);
            this.Controls.Add(this.axLicenseControl1);
            this.Controls.Add(this.axMapControl1);
            this.Controls.Add(this.cmdFullExtent);
            this.Controls.Add(this.Label3);
            this.Controls.Add(this.chkShowTips);
            this.Controls.Add(this.cmdLoadData);
            this.Controls.Add(this.cboDataField);
            this.Controls.Add(this.cboDataLayer);
            this.Controls.Add(this.Label2);
            this.Controls.Add(this.Label1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.Load += new System.EventHandler(this.Form1_Load);
            ((System.ComponentModel.ISupportInitialize)(this.axMapControl1)).EndInit();
            ((System.ComponentModel.ISupportInitialize)(this.axLicenseControl1)).EndInit();
            this.ResumeLayout(false);
            this.PerformLayout();

    }
    #endregion

    [STAThread]
    static void Main() 
    {
            if (!RuntimeManager.Bind(ProductCode.Engine))
            {
                if (!RuntimeManager.Bind(ProductCode.Desktop))
                {
                    MessageBox.Show("Unable to bind to ArcGIS runtime. Application will be shut down.");
                    return;
                }
            }

            Application.Run(new Form1());
    }

    private void Form1_Load(object sender, System.EventArgs e)
    {
      //Disable controls
      chkShowTips.Enabled = false;
            chkTransparent.Enabled = false;
      cboDataLayer.Enabled = false;
      cboDataField.Enabled = false;
    }

    private void cboDataLayer_SelectedIndexChanged(object sender, System.EventArgs e)
    {
      //Disable field combo if feature layer is not selected and exit
      if (axMapControl1.get_Layer(cboDataLayer.SelectedIndex) is IFeatureLayer == false)
      {
        cboDataField.Items.Clear();
        cboDataField.Enabled = false;
        return;
      }

      //Get IFeatureLayer interface
      IFeatureLayer featureLayer = (IFeatureLayer) axMapControl1.get_Layer(cboDataLayer.SelectedIndex);
      //Query interface for ILayerFields
      ILayerFields layerFields = (ILayerFields) featureLayer;

      int j = 0;
      cboDataField.Items.Clear();
      cboDataField.Enabled = true;
      //Loop through the fields
      for (int i = 0; i <= layerFields.FieldCount - 1; i++)
      {
        //Get IField interface
        IField field = layerFields.get_Field(i);
        //If the field is not the shape field
        if (field.Type != esriFieldType.esriFieldTypeGeometry)
        {
          //Add field name to the control
          cboDataField.Items.Insert(j, field.Name);
          //If the field name is the display field
          if (field.Name == featureLayer.DisplayField)
          {
            //Select the field name in the control
            cboDataField.SelectedIndex = j;
          }
          j = j + 1;
        }
      }
      ShowLayerTips();
    }

    private void chkShowTips_CheckStateChanged(object sender, System.EventArgs e)
    {
      ShowLayerTips();
    }

    private void cmdFullExtent_Click(object sender, System.EventArgs e)
    {
      //Zoom to full extent of data
      axMapControl1.Extent = axMapControl1.FullExtent;
    }

    private void cmdLoadData_Click(object sender, System.EventArgs e)
    {
      openFileDialog1.Title = "Browse Map Document";
      openFileDialog1.Filter = "Map Documents (*.mxd)|*.mxd";
      openFileDialog1.ShowDialog();

      //Exit if no map document is selected
      string sFilePath = openFileDialog1.FileName;
      if (sFilePath == "")
      {
        return;
      }

      //Validate and load map document
      if (axMapControl1.CheckMxFile(sFilePath)== true)
      {
        axMapControl1.LoadMxFile(sFilePath,Type.Missing,"");
        //Enabled MapControl
        axMapControl1.Enabled = true;
      }
      else
      {
        MessageBox.Show(sFilePath + " is not a valid ArcMap document");
          return;
      }

      //Add the layer names to combo
      cboDataLayer.Items.Clear();
      for (int i = 0; i <= axMapControl1.LayerCount - 1; i++)
      {
        cboDataLayer.Items.Insert(i, axMapControl1.get_Layer(i).Name);
      }

      //Select first layer in control
      cboDataLayer.SelectedIndex = 0;
      //Enable controls if disabled
      if (chkShowTips.Enabled == false) chkShowTips.Enabled = true;
            if (chkTransparent.Enabled == false) chkTransparent.Enabled = true;
      if (cboDataLayer.Enabled == false) cboDataLayer.Enabled = true;
      if (cboDataField.Enabled == false) cboDataField.Enabled = true;
    }

    private void ShowLayerTips()
    {
      //Loop through the maps layers
      for (int i = 0; i <= axMapControl1.LayerCount - 1; i++)
      {
        //Get ILayer interface
        ILayer layer = axMapControl1.get_Layer(i);
        //If is the layer selected in the control
        if (cboDataLayer.SelectedIndex == i)
        {
          //If want to show map tips
          if (chkShowTips.CheckState == CheckState.Checked)
          {
            layer.ShowTips = true;
          }
          else
          {
            layer.ShowTips = false;
          }
        }
        else
        {
          layer.ShowTips = false;
        }
      }
    }

    private void cboDataField_SelectedIndexChanged(object sender, System.EventArgs e)
    {
      //Get IFeatureLayer interface 
      IFeatureLayer featureLayer = (IFeatureLayer) axMapControl1.get_Layer(cboDataLayer.SelectedIndex);
      //Query interface for IlayerFields
      ILayerFields layerFields = (ILayerFields) featureLayer;

      //Loop through the fields
      for (int i = 0; i <= layerFields.FieldCount - 1; i++)
      {
        //Get IField interface
        IField field = layerFields.get_Field(i);
        //If the field name is the name selected in the control
        if (field.Name == cboDataField.Text)
        {
          //Set the field as the display field
          featureLayer.DisplayField = field.Name;
          break;
        }
      }
    }

    private void axMapControl1_OnMouseDown(object sender, ESRI.ArcGIS.Controls.IMapControlEvents2_OnMouseDownEvent e)
    {
      //If left mouse button zoom in
      if (e.button == 1)
      {
        axMapControl1.Extent = axMapControl1.TrackRectangle();
      }
        //If right mouse button pan
      else if (e.button == 2)
      {
        axMapControl1.Pan();
      }
    }

        private void chkShowTips_CheckedChanged(object sender, EventArgs e)
        {
            if (chkShowTips.CheckState == CheckState.Checked)
                axMapControl1.ShowMapTips = true;
            else
                axMapControl1.ShowMapTips = false;
        }

        private void chkTransparent_CheckedChanged(object sender, EventArgs e)
        {
            if (chkTransparent.CheckState == CheckState.Checked)
                axMapControl1.TipStyle = esriTipStyle.esriTipStyleTransparent;
            else
                axMapControl1.TipStyle = esriTipStyle.esriTipStyleSolid;
        }

  }
}