自定义按钮（转）-.NET教程,Windows开发

//这个用户自定义控件继承自button类
//实现了在按纽左侧显示图片的任务
//和点击后显示不同样式的功能
//下面就是人家的了
//本人加如了一些注释

using system;
using system.windows.forms;
using system.drawing;

namespace nettoggle
{
    /// <summary>
    /// summary description for customflatbutton.
    /// </summary>
    public class customflatbutton : system.windows.forms.button
    {    
        //used to set the type of image that is displayed with the button
        public enum toggle_type{ none, xml_toggle, html_toggle };//显示类型

        private bool bselected = false;//是否被选择
        private system.windows.forms.imagelist flatbtnimagelist;//从工具栏拖进来的了
        //他的一些东西有vs.net工具自动生成
        private system.componentmodel.icontainer components;
        private int toggletype = 0;

        public int toggletype
        {
            get{ return toggletype; }
            set{ toggletype = value; }
        }

        public bool bchangeselection
        {
            get{ return bselected; }
            set{ bselected = value; invalidate(); }
        }
        
        public customflatbutton()
        {
            initializecomponent();
        }
        
        private void initializecomponent()
        {
            this.components = new system.componentmodel.container();
            system.resources.resourcemanager resources = new system.resources.resourcemanager(typeof(customflatbutton));
            this.flatbtnimagelist = new system.windows.forms.imagelist(this.components);
            //
            // flatbtnimagelist
            //
            this.flatbtnimagelist.colordepth = system.windows.forms.colordepth.depth8bit;
            this.flatbtnimagelist.imagesize = new system.drawing.size(9, 9);
            this.flatbtnimagelist.imagestream = ((system.windows.forms.imageliststreamer)(resources.getobject("flatbtnimagelist.imagestream")));
            this.flatbtnimagelist.transparentcolor = system.drawing.color.transparent;
            //
            // customflatbutton
            //
            this.flatstyle = system.windows.forms.flatstyle.flat;
            this.font = new system.drawing.font("tahoma", 8.25f, system.drawing.fontstyle.regular, system.drawing.graphicsunit.point, ((system.byte)(0)));
            this.size = new system.drawing.size(57, 19);

        }

        protected override void onmouseenter( system.eventargs e )
        {
            return;
        }

        protected override void onclick( system.eventargs e)
        {
            bselected = true;//触发bchangeselection的写属性–调用this.invalidate();–引起对onpaint()的调用
            base.onclick(e);
        }
        
        protected override void onmousedown( system.windows.forms.mouseeventargs e)
        {
            onclick(e);
        }

        protected override void onpaint( system.windows.forms.painteventargs e )
        {
            rectangle rect = e.cliprectangle;
            graphics g = e.graphics;

            if( bselected )
            {
                g.fillrectangle( new solidbrush(color.white), rect );
                g.drawstring( this.text, this.font, new solidbrush(this.forecolor), 20, (float)2.5 );

                g.drawrectangle( new pen(system.drawing.systemcolors.highlight, 2), rect );
            }
            else
            {
                g.fillrectangle( new solidbrush(system.drawing.systemcolors.control), rect );
                g.drawstring( this.text, this.font, new solidbrush(this.forecolor),  20, (float)2.5 );
            }
        
            //now draw the correct image if one is specified
            if( toggletype == (int)toggle_type.xml_toggle )
                g.drawimage( this.flatbtnimagelist.images[0], 8, 5 );
            else if( toggletype == (int)toggle_type.html_toggle )
                g.drawimage( this.flatbtnimagelist.images[1], 7, 5 );
        }
    }
}