Changing layout background from red to blue through button add-in with C# and ArcObjects?

Question

I am working on Arc Objects using C# and I have to make a button add in, such that if I click button one time then layout background color changes to red and then if I click again then button add in change the background color from red to blue in Arc Map. I have successfully changed layout background color to red and blue but I want that color keep changing on each click from red to blue and then from blue to green.

Here is my code:

using ESRI.ArcGIS.Framework;
using ESRI.ArcGIS.esriSystem;
using ESRI.ArcGIS.Display;
using ESRI.ArcGIS.Desktop.AddIns;
using ESRI.ArcGIS.Carto;
using ESRI.ArcGIS.ArcMapUI;
using System;
using System.Collections.Generic;
using System.Text;
using System.IO;

namespace lecture5test
{
    public class Button1 : ESRI.ArcGIS.Desktop.AddIns.Button
    {
        public Button1()
        {

        }
        protected override void OnClick()
        {
            //
            //  TODO: Sample code showing how to access button host
            //

            ArcMap.Application.CurrentTool = null;

            RgbColor r = new RgbColor();
            IRgbColor iRgb = (IRgbColor)r;
            iRgb.Red = 255;
            iRgb.Green = 0;
            iRgb.Blue = 0;
            IColor ic = (IColor)r;
            // Page iPl = ArcMap.Document.PageLayout;
            IPageLayout iPl = ArcMap.Document.PageLayout;
            IPage pPage = (IPage)iPl.Page;

            RgbColor b = new RgbColor();
            IRgbColor bRgb = (IRgbColor)b;
            bRgb.Red = 0;
            bRgb.Green = 0;
            bRgb.Blue = 255;
            IColor ib = (IColor)b;

            RgbColor g = new RgbColor();
            IRgbColor gRgb = (IRgbColor)g;
            gRgb.Red = 0;
            gRgb.Green = 255;
            gRgb.Blue = 0;
            IColor ig = (IColor)g;

            pPage.BackgroundColor = ic;
            pPage.BackgroundColor = ib;
            pPage.BackgroundColor = ig;


        }

        private void EnableDynamicDisplay()
        {
            throw new NotImplementedException();
        }
        protected override void OnUpdate()
        {
            Enabled = ArcMap.Application != null;

        }

    }

}

Answer 1

Red -> Blue -> Green -> Red etc.

Just wrap your pPage.BackgroundColor = in if/else if/else something like

if (pPage.BackgroundColor.RGB == ic.RGB)
{ 
    pPage.BackgroundColor = ib;
}
else if (pPage.BackgroundColor.RGB == ib.RGB)
{
    pPage.BackgroundColor = ig;
}
else
{
    pPage.BackgroundColor = ic;
}

Answer 2

This is a good case for a global variable:

namespace lecture5test
{
    public class Button1 : ESRI.ArcGIS.Desktop.AddIns.Button
    {
        private int ClickCount = 0; // global to keep track of clicks

        public Button1()
        {

then in your OnClick event:

protected override void OnClick()
{
    ClickCount ++; // go to next click colour
    if (ClickCount > 3)
    {
        ClickCount = 1; // out of range, go back to first
    }

// lines of code

if (ClickCount == 1)
{
    pPage.BackgroundColor = ic;
}
else if (ClickCount == 2)
{
    pPage.BackgroundColor = ib;
}
else if (ClickCount == 3)
{
    pPage.BackgroundColor = ig;
}

This will allow you to step through the colours with a click.