How do I implement a TextBox that displays "Type here"?
Based on @Pooven's answer (thank you!), I created this class. Works for me.
/// <summary>
/// A textbox that supports a watermak hint.
/// </summary>
public class WatermarkTextBox : TextBox
{
/// <summary>
/// The text that will be presented as the watermak hint
/// </summary>
private string _watermarkText = "Type here";
/// <summary>
/// Gets or Sets the text that will be presented as the watermak hint
/// </summary>
public string WatermarkText
{
get { return _watermarkText; }
set { _watermarkText = value; }
}
/// <summary>
/// Whether watermark effect is enabled or not
/// </summary>
private bool _watermarkActive = true;
/// <summary>
/// Gets or Sets whether watermark effect is enabled or not
/// </summary>
public bool WatermarkActive
{
get { return _watermarkActive; }
set { _watermarkActive = value; }
}
/// <summary>
/// Create a new TextBox that supports watermak hint
/// </summary>
public WatermarkTextBox()
{
this._watermarkActive = true;
this.Text = _watermarkText;
this.ForeColor = Color.Gray;
GotFocus += (source, e) =>
{
RemoveWatermak();
};
LostFocus += (source, e) =>
{
ApplyWatermark();
};
}
/// <summary>
/// Remove watermark from the textbox
/// </summary>
public void RemoveWatermak()
{
if (this._watermarkActive)
{
this._watermarkActive = false;
this.Text = "";
this.ForeColor = Color.Black;
}
}
/// <summary>
/// Applywatermak immediately
/// </summary>
public void ApplyWatermark()
{
if (!this._watermarkActive && string.IsNullOrEmpty(this.Text)
|| ForeColor == Color.Gray )
{
this._watermarkActive = true;
this.Text = _watermarkText;
this.ForeColor = Color.Gray;
}
}
/// <summary>
/// Apply watermak to the textbox.
/// </summary>
/// <param name="newText">Text to apply</param>
public void ApplyWatermark(string newText)
{
WatermarkText = newText;
ApplyWatermark();
}
}
What you're looking for is a TextBox with a "watermark".
There's a sample implementation for C# here, all credits to Wael Alghool.
The relevant part of his code is:
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();
}
}
}
}
Something that has worked for me:
this.waterMarkActive = true;
this.textBox.ForeColor = Color.Gray;
this.textBox.Text = "Type here";
this.textBox.GotFocus += (source, e) =>
{
if (this.waterMarkActive)
{
this.waterMarkActive = false;
this.textBox.Text = "";
this.textBox.ForeColor = Color.Black;
}
};
this.textBox.LostFocus += (source, e) =>
{
if (!this.waterMarkActive && string.IsNullOrEmpty(this.textBox.Text))
{
this.waterMarkActive = true;
this.textBox.Text = "Type here";
this.textBox.ForeColor = Color.Gray;
}
};
Where bool waterMarkActive is a class member variable and textBox is the TextBox. This probably should be encapsulated though :) There might be some issues with this approach, but I'm not currently aware of any.
I recently discovered that Windows support water marks in text boxes; they are called cue banners (see here). It's very easy to implement:
// Within your class or scoped in a more appropriate location:
[DllImport("user32.dll")]
private static extern IntPtr SendMessage(IntPtr hWnd, int Msg, int wParam, [MarshalAs(UnmanagedType.LPWStr)] string lParam);
// In your constructor or somewhere more suitable:
SendMessage(textBox.Handle, 0x1501, 1, "Please type here.");
Where textBox is an instance of TextBox, 0x1501 is the code for the windows message EM_SETCUEBANNER, the wParam may either be TRUE (non-zero) or FALSE (zero), and lParam is the water mark you'd like to display. wParam indicates when the cue banner should be displayed; if set to TRUE then the cue banner will be displayed even when the control has focus.