ASP.NET Required TextBox (Graphical RequiredFieldValidator)

/*
==============================================================================
	Click2Install Software Custom ASP.NET Control Library
	
  Class:         RequiredTextBox.cs
  Functionality: Custom Designed ASP.NET TextBox with built-in RequiredField 
                 Validation.
  
  Copyright � 2001-2006 Click2Install Software
	Copyright � Maurice Moore (info@click2install.com)
		
	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.
	
	See the GNU General Public License for more details.
	
==============================================================================
*/
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
using click2install.design;
using System.Drawing.Design;

namespace click2install.controls
{
  [
   ToolboxData("<{0}:RequiredTextBox runat=server></{0}:RequiredTextBox>"),
   Designer(typeof(RequiredTextBoxDesigner)),
  ]
  public class RequiredTextBox : TextBox
  {

    #region constants

    private const string DEFAULT_VALIDATOR_TEXT = "&nbsp;*";

    #endregion

    public RequiredTextBox()
    {
      ValidatorDisplayType = ValidatorDisplay.Dynamic;
      ValidatorEnableClientScript = true;
      ValidatorFocusOnError = true;
    }


    #region Required Field Validator properties

    [
     Browsable(false),
    ]
    private RequiredValidator m_RequiredFieldValidator = null;
    /// <summary>
    /// Gets or sets the required text box validator.
    /// </summary>
    /// <value>The required text box validator.</value>
    private RequiredValidator RequiredTextBoxValidator
    {
      get
      {
        if (m_RequiredFieldValidator == null) { m_RequiredFieldValidator = new RequiredValidator(this); }
        return m_RequiredFieldValidator;
      }
      set { m_RequiredFieldValidator = value; }
    }

    /// <summary>
    /// Gets a value indicating whether this instance is design mode.
    /// </summary>
    /// <value>
    /// 	<c>true</c> if this instance is design mode; otherwise, <c>false</c>.
    /// </value>
    internal bool IsDesignMode
    {
      get { return DesignMode; }
    }

    private ErrorProviderType m_ErrorProvider = ErrorProviderType.StillIcon;
    /// <summary>
    /// Gets or sets the error provider.
    /// </summary>
    /// <value>The error provider.</value>
    [
     Description("The type of visual alert that will be shown when validation fails"),
     Category("Validator"),
     DefaultValue(ErrorProviderType.StillIcon),
    ]
    public ErrorProviderType ErrorProvider
    {
      get { return m_ErrorProvider; }
      set 
      {
        if (value == ErrorProviderType.Text) { RequiredTextBoxValidator.Text = DEFAULT_VALIDATOR_TEXT; }
        m_ErrorProvider = value; 
      }
    }

    /// <summary>
    /// Gets or sets the validator message.
    /// </summary>
    /// <value>The validator message.</value>
    [
     Description("The Validators Message when validation fails"),
     Category("Validator"),
    ]
    public string ValidatorMessage
    {
      get { return RequiredTextBoxValidator.ErrorMessage; }
      set { RequiredTextBoxValidator.ErrorMessage = value; }
    }

    /// <summary>
    /// Gets or sets the type of the validator display.
    /// </summary>
    /// <value>The type of the validator display.</value>
    [
     Description("The Validators Display"),
     Category("Validator"),
    ]
    public ValidatorDisplay ValidatorDisplayType
    {
      get { return RequiredTextBoxValidator.Display; }
      set { RequiredTextBoxValidator.Display = value; }
    }


    /// <summary>
    /// Gets or sets the validator text.
    /// </summary>
    /// <value>The validator text.</value>
    [
     Description("Whether the ErrorProvider icons are rendered in Design Mode or not."),
     Category("Validator"),
    ]
    public bool RenderDesignModeValidatorIcon
    {
      get { return RequiredTextBoxValidator.RenderDesignModeErrorProvider; }
      set { RequiredTextBoxValidator.RenderDesignModeErrorProvider = value; }
    }

    /// <summary>
    /// Gets or sets a value indicating whether [validator focus on error].
    /// </summary>
    /// <value>
    /// 	<c>true</c> if [validator focus on error]; otherwise, <c>false</c>.
    /// </value>
    [
     Description("The Validators FocusOnError"),
     Category("Validator"),
    ]
    public bool ValidatorFocusOnError
    {
      get { return RequiredTextBoxValidator.SetFocusOnError; }
      set { RequiredTextBoxValidator.SetFocusOnError = value; }
    }

    /// <summary>
    /// Gets or sets a value indicating whether [validator enable client script].
    /// </summary>
    /// <value>
    /// 	<c>true</c> if [validator enable client script]; otherwise, <c>false</c>.
    /// </value>
    [
     Description("The Validators EnableClientScript"),
     Category("Validator"),
    ]
    public bool ValidatorEnableClientScript
    {
      get { return RequiredTextBoxValidator.EnableClientScript; }
      set { RequiredTextBoxValidator.EnableClientScript = value; }
    }

    #endregion

    /// <summary>
    /// Raises the <see cref="E:System.Web.UI.Control.Init"></see> event.
    /// </summary>
    /// <param name="e">An <see cref="T:System.EventArgs"></see> object that contains the event data.</param>
    protected override void OnInit(EventArgs e)
    {
      Controls.Clear();

      this.ID = base.UniqueID;
      RequiredTextBoxValidator.TextBox = this;

      RequiredTextBoxValidator.ControlToValidate = this.ID;
      RequiredTextBoxValidator.EnableClientScript = ValidatorEnableClientScript;
      RequiredTextBoxValidator.Enabled = true;
      RequiredTextBoxValidator.ValidationGroup = this.ValidationGroup;
      RequiredTextBoxValidator.Text = (ErrorProvider == ErrorProviderType.Text) ? DEFAULT_VALIDATOR_TEXT : string.Empty;
      RequiredTextBoxValidator.ErrorMessage = ValidatorMessage;
      RequiredTextBoxValidator.Display = ValidatorDisplayType;
      RequiredTextBoxValidator.SetFocusOnError = ValidatorFocusOnError;

      Controls.Add(RequiredTextBoxValidator);
    }

    /// <summary>
    /// Renders the <see cref="T:System.Web.UI.WebControls.TextBox"></see> control to the specified <see cref="T:System.Web.UI.HtmlTextWriter"></see> object.
    /// </summary>
    /// <param name="writer">The <see cref="T:System.Web.UI.HtmlTextWriter"></see> that receives the rendered output.</param>
    protected override void Render(HtmlTextWriter writer)
    {
      writer.RenderBeginTag(HtmlTextWriterTag.Span);

      base.Render(writer);

      RequiredTextBoxValidator.RenderControl(writer);

      writer.RenderEndTag();
    }
  }
}