WaterMark TextBox Application C#

From: http://www.codeproject.com/KB/miscctrl/WaterMark.aspx

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing;

namespace wmgCMS
{
   class WaterMarkTextBox : TextBox
   {
       private Font oldFont = null;
       private Boolean waterMarkTextEnabled = false;

       #region Attributes
           private Color _waterMarkColor = Color.Gray;
           public Color WaterMarkColor
           {
               get { return _waterMarkColor; }
               set { _waterMarkColor = value; Invalidate();/*thanks to Bernhard Elbl
                                                             for Invalidate()*/ }
           }

           private string _waterMarkText = "Water Mark";
           public string WaterMarkText
           {
               get { return _waterMarkText; }
               set { _waterMarkText = value; Invalidate(); }
           }
       #endregion

       //Default constructor
       public WaterMarkTextBox()
       {
           JoinEvents(true);
       }

       //Override OnCreateControl ... thanks to  "lpgray .. codeproject guy"
       protected override void OnCreateControl()
       {
           base.OnCreateControl();
           WaterMark_Toggel(null, null);
       }
      
       //Override OnPaint
       protected override void OnPaint(PaintEventArgs args)
       {
           // Use the same font that was defined in base class
           System.Drawing.Font drawFont = new System.Drawing.Font(Font.FontFamily,
               Font.Size, Font.Style, Font.Unit);
           //Create new brush with gray color or 
           SolidBrush drawBrush = new SolidBrush(WaterMarkColor);//use Water mark color
           //Draw Text or WaterMark
           args.Graphics.DrawString((waterMarkTextEnabled ? WaterMarkText : Text),
               drawFont, drawBrush, new PointF(0.0F, 0.0F));
           base.OnPaint(args);
       }

       private void JoinEvents(Boolean join)
       {
           if (join)
           {
               this.TextChanged += new System.EventHandler(this.WaterMark_Toggel);
               this.LostFocus += new System.EventHandler(this.WaterMark_Toggel);
               this.FontChanged += new System.EventHandler(this.WaterMark_FontChanged);
               //No one of the above events will start immeddiatlly 
               //TextBox control still in constructing, so,
               //Font object (for example) couldn't be catched from within
               //WaterMark_Toggle
               //So, call WaterMark_Toggel through OnCreateControl after TextBox
               //is totally created
               //No doupt, it will be only one time call
              
               //Old solution uses Timer.Tick event to check Create property
           }
       }

       private void WaterMark_Toggel(object sender, EventArgs args )
       {
           if (this.Text.Length <= 0)
               EnableWaterMark();
           else
               DisbaleWaterMark();
       }

       private void EnableWaterMark()
       {
           //Save current font until returning the UserPaint style to false (NOTE:
           //It is a try and error advice)
           oldFont = new System.Drawing.Font(Font.FontFamily, Font.Size, Font.Style,
              Font.Unit);
           //Enable OnPaint event handler
           this.SetStyle(ControlStyles.UserPaint, true);
           this.waterMarkTextEnabled = true;
           //Triger OnPaint immediatly
           Refresh();
       }

       private void DisbaleWaterMark()
       {
           //Disbale OnPaint event handler
           this.waterMarkTextEnabled = false;
           this.SetStyle(ControlStyles.UserPaint, false);
           //Return back oldFont if existed
           if(oldFont != null)
               this.Font = new System.Drawing.Font(oldFont.FontFamily, oldFont.Size,
                   oldFont.Style, oldFont.Unit);
       }

       private void WaterMark_FontChanged(object sender, EventArgs args)
       {
           if (waterMarkTextEnabled)
           {
               oldFont = new System.Drawing.Font(Font.FontFamily,Font.Size,Font.Style,
                   Font.Unit);
               Refresh();
           }
       }
   }
}

About the Author

Wael Alghool Member

Programming since 1990. I'm Experience in VC++, COM, MFC, API, ISAPI, ASP.NET, C#, jQuery, SQLite, SQL2005, Fatwire-CMS and J2EE. Since 2004, I'm SME (Subject matter expert) in requirements gathering. Since 2005, I'm PSP (Personal Software Process) certified. Since 2005, I Lead teams in between 8 to 30 members in several companies. Since 1999, I Worked for international companies like Harf-IT, ISlamweb, Qatar-awqaf ministry and Islamonline. Occupation: Architect Company: Government Location: Qatar