用动态控件模拟复合控件

    动态控件，复合控件，相信大家都已经很熟悉了。只要达到同样的展示及功能，用什么样的方式实现应该取决于实际情况。我在一个项目中遇到的情况是：已经有了很多页面，但每个页面都没有用Validation控件来验证输入的有效性。

    为了达到相同的展示效果：

    常规办法：是为每个页面的每个TextBox有选择的生成RequiredFieldValidator、RangeValidator、CompareValidator、RegularExpressionValidator、FilteredTextBoxExtender。但这个方法，需要每个页面都去添加，并且统一调整起效果来，工作量太大。

    复合控件：是写一个复合控件，依参数来添加验证控件。这个也需要在页面中统一添加一次（工作量约为第一个办法的1/3），还需要更改一下后台的控件类型声明(我的后台代码在另一个程序集中)。

    动态控件：写了个直接继承自TextBox的控件，在适当的地方，依参数来添加验证控件。这个也需要在页面中统一改动一下（工作量和复合控件的方法相当），不过，后台的代码不用做发改动。

    前两种，大家不陌生，我就不啰嗦了。这里，只说一下用动态控件实现上面功能的方法。

    先展望一下使用方法：

        <!-- 必须输入  -->
        <facade:StringTextBox Options="required" HelpMessage="请输入用户名"  DisplayName="用户名"  
            runat="server" ID="StringTextBox1" MaxLength = "30" /><br />
        <!-- 必须输入，只能输入数字  -->
        <facade:StringTextBox Options="required,Filtered" HelpMessage="请输入用户名"  
            FilterType="Numbers" DisplayName="用户名"  runat="server" ID="StringTextBox2" MaxLength = "30" /><br />
        
         <!-- 必须输入，只能输入数字，数值范围是0－400  -->
        <facade:NumberTextBox runat="server" ID = "tbCount" MinValue="0" MaxValue="400" DisplayName="数量"  
            HelpMessage="请输入数量" />
         <!-- 必须输入，只能输入数字，数值范围是0－400  -->
        <facade:MoneyTextBox runat="server" ID = "NumberTextBox1" MinValue="0" MaxValue="400" 
            DisplayName="金额"  HelpMessage="请输入金额" />
        
         <!-- 必须输入，输入的字符串必须以ABC开头  -->
        <facade:RegexTextBox runat="server" Options="Required" ValidationExpression="^abc.+$" 
            ID="tbRegex" DisplayName="正则测试" MaxLength="120" Example="abc123,abceee" HelpMessage="请输入正则测试" />
         <!-- 输入的必须是手机号  -->
        <facade:PhoneTextBox runat="server" ID="tbMobile"  PhoneTypes="Mobile" DisplayName="手机号" 
            MaxLength="20" Example="13988888888" HelpMessage="请输入手机号" />
         <!-- 输入的必须是手机号，或者电话  -->
        <facade:PhoneTextBox runat="server" ID="tbPhoneMobile"  PhoneTypes="Phone,Mobile" DisplayName="手机号"
             MaxLength="20" Example="13988888888，0311-88886666" HelpMessage="请输入手机号" />

    动态控件的添加，应该在Page.PreInit中添加，因为此时控件还没有加载ViewState。但控件中得不到Page.PreInit事件，我们遇到了第一个难题；

    如果TextBox控件中模板中，则只有在Page.PreRender时，我们才能得到控件实例，所以只在Page.PreInit中添加控件不行，我们还必须在PreRender时，看看这个TextBox有没有添加动态控件，如果添加了，再添加就要报错了，在Page.PreRender时添加控件，是我们的第二个难题 。

    还好，这两个问题是一类问题，我们通过写一个HttpModuler，来帮助控件得到Page.PreInit和Page.PreRender事件，还要有一个HttpModuler和控件都能访问的地方：BaseTextBoxContext，来把所有的控件事件放在这里。代码如下：

    /// <summary>
    /// HttpModuler和控件的交互对象
    /// </summary>
    public class BaseTextBoxContext
    {
        private static readonly string item_key = "::grain.basetextbox.context";

        private static LocalDataStoreSlot GetSlot()
        {
            return Thread.GetNamedDataSlot(item_key);
        }

        /// <summary>
        /// 当前线程上下文的对象
        /// </summary>
        public static BaseTextBoxContext Current
        {
            get
            {
                BaseTextBoxContext current = Thread.GetData(GetSlot()) as BaseTextBoxContext;
                if (current == null)
                {
                    current = new BaseTextBoxContext();
                    Thread.SetData(GetSlot(), current);
                }

                return current;
            }
        }


        /// <summary>
        /// 移除线程上下文 
        /// </summary>
        public void RemoveContext()
        {
            Thread.FreeNamedDataSlot(item_key);
        }


        private List<EventHandler> preInitHandlers = new List<EventHandler>();


        /// <summary>
        /// 控件的PreInit事件响应函数列表
        /// </summary>
        public List<EventHandler> PreInitHandlers
        {
            get { return preInitHandlers; }
        }


        /// <summary>
        /// 添加一个PreInit时的响应函数
        /// </summary>
        /// <param name="eventHandler"></param>
        public void AddPagePreInit(EventHandler eventHandler)
        {
            PreInitHandlers.Add(eventHandler);
        }

        private List<EventHandler> preRenderHandlers = new List<EventHandler>();
        /// <summary>
        /// 控件的PreRender事件响应函数列表
        /// </summary>
        public List<EventHandler> PreRenderHandlers
        {
            get { return preRenderHandlers; }
        }

        /// <summary>
        /// 添加一个PreRender时的响应函数
        /// </summary>
        /// <param name="eventHandler"></param>
        public void AddPagePreRender(EventHandler eventHandler)
        {
            preRenderHandlers.Add(eventHandler);

        }
    }

    /// <summary>
    /// 帮助BaseTextBox响应Page.PreInit和Page.PreRender类
    /// </summary>
    public class BaseTextBoxModule : IHttpModule
    {

        #region IHttpModule Members

        public void Dispose()
        {
            
        }

        public void Init(HttpApplication context)
        {
            context.PreRequestHandlerExecute += new EventHandler(context_PreRequestHandlerExecute);
            context.PostRequestHandlerExecute += new EventHandler(context_PostRequestHandlerExecute);
            
        }

        void context_PostRequestHandlerExecute(object sender, EventArgs e)
        {
            //页面执行结束，清理
            BaseTextBoxContext.Current.RemoveContext();
        }

        void context_PreRequestHandlerExecute(object sender, EventArgs e)
        {
            Page page = HttpContext.Current.CurrentHandler as Page;
            if (page != null)
            {
                //注册页面的PreInit和PreRender事件
                page.PreInit += new EventHandler(Page_PreInit);
                page.PreRenderComplete += new EventHandler(page_PreRenderComplete);
            }

        }

        void page_PreRenderComplete(object sender, EventArgs e)
        {
            try
            {
                List<EventHandler> list = new List<EventHandler>(BaseTextBoxContext.Current.PreRenderHandlers);
                foreach (EventHandler handler in list)
                {
                    //执行控件要求要PreRender时的事件函数
                    handler.Invoke(sender, e);
                }
            }
            finally
            {

                BaseTextBoxContext.Current.PreRenderHandlers.Clear();
            }
        }



        void Page_PreInit(object sender, EventArgs e)
        {
            try
            {
                List<EventHandler> list = new List<EventHandler>(BaseTextBoxContext.Current.PreInitHandlers);
                foreach (EventHandler handler in list)
                {
                    //执行控件要求要PreInit时的事件函数
                    handler.Invoke(sender, e);
                }
            }
            finally
            {

                BaseTextBoxContext.Current.PreInitHandlers.Clear();
            }
        }

        #endregion
    }

现在第一个问题和第二个问题的一部分解决了。为了在Page.PreInit之前，让用户控件自己把自己的事件添加到BaseTextBoxContext中，我在BaseTextBox的构造函数中，调用

        public BaseTextBox()
        {
            BaseTextBoxContext.Current.AddPagePreInit(new EventHandler(Page_PreInit));
        }

把自己要在Page.PreInit中执行的函数添加进去。在控件的Page_PreInit时， 我们要添加动态控件，还可以把自己放在另一个动态控件的内部哟，比如把TextBox放在Panel中，生成类似：

<div class="input_wrapper">
    <input type="text" />
    <span class="helpmessage">help message here</span>
    <!--这里放置动态验证控件-->
</div>

下面是我的实现：

    [Flags]
    public enum TextBoxOptions
    {
        None = 0,
        Required = 1,
        Filtered = 2
    }


    public class BaseTextBox : TextBox
    {
        private bool preRendered = false;
        private bool buildValidatorControls = false;

        public BaseTextBox()
        {
            BaseTextBoxContext.Current.AddPagePreInit(new EventHandler(Page_PreInit));
        }

        void Page_PreInit(object sender, EventArgs e)
        {
            if (!buildValidatorControls)
            {
                buildValidatorControls = true;
                BuildValidatorControls();
            }
        }


        void EnableValidatorControls(object sender, EventArgs e)
        {
            if (preRendered)
            {
                if (!buildValidatorControls)
                {
                    buildValidatorControls = true;
                    BuildValidatorControls();
                }
            }
        }

        private Panel parentWrap;

        public Panel ParentWrap
        {
            get {
                if (parentWrap == null)
                {
                    parentWrap = new Panel() { CssClass = "input_wrapper" };

                    this.Parent.Controls.AddAt(this.Parent.Controls.IndexOf(this), parentWrap);
                    this.Parent.Controls.Remove(this);
                    
                    parentWrap.Controls.Add(this);
                }
                
                return parentWrap; 
            }
        }
        private ValidatorDisplay display = ValidatorDisplay.Dynamic;

        /// <summary>
        /// 验证控件显示方式
        /// </summary>
        public ValidatorDisplay ValidatorDisplay
        {
            get { return display; }
            set { display = value; }
        }

        private string validatorGroup = string.Empty;

        /// <summary>
        /// 验证分组
        /// </summary>
        public string ValidatorGroup
        {
            get { return validatorGroup; }
            set { validatorGroup = value; }
        }



        private FilterTypes filterType;

        /// <summary>
        /// 过滤类型
        /// </summary>
        public FilterTypes FilterType
        {
            get { return filterType; }
            set { filterType = value; }
        }

        private string invalidChars = string.Empty;

        /// <summary>
        /// 过滤时的无效字符,这些字符不能输入
        /// </summary>
        public string InvalidChars
        {
            get { return invalidChars; }
            set { invalidChars = value; }
        }

        private string validChars = string.Empty;

        /// <summary>
        /// 过滤时的有效字符,除这些字符外其它字符不能输入
        /// </summary>
        public string ValidChars
        {
            get { return validChars; }
            set { validChars = value; }
        }
        private String helpMessage = string.Empty;

        /// <summary>
        /// 当获得焦点时,提示的文本
        /// </summary>
        public String HelpMessage
        {
            get { return helpMessage; }
            set { helpMessage = value; }
        }


        /// <summary>
        /// 如果有示例,在提示文本中加上
        /// </summary>
        /// <returns></returns>
        private string GetHelpMessage()
        {
            return string.Format("{0}  {1}",HelpMessage , this.GetExampleString());
        }

        private String displayName = string.Empty;

        /// <summary>
        /// 出错提示时使用的控件ID的中文名字
        /// </summary>
        public String DisplayName
        {
            get {
                if (string.IsNullOrEmpty(this.displayName))
                    return this.ID;

                return displayName; 
            }
            set { displayName = value; }
        }


        private string example = string.Empty;

        /// <summary>
        /// 示例文本
        /// </summary>
        public string Example
        {
            get { return example; }
            set { example = value; }
        }

        protected string GetExampleString()
        {
            return string.IsNullOrEmpty(this.Example) ? string.Empty : string.Format("示例:{0}", this.Example);
        }

        private TextBoxOptions options = TextBoxOptions.None;


        /// <summary>
        /// 文本框选项
        /// </summary>
        public TextBoxOptions Options
        {
            get { return options; }
            set {options =value;}
        }
        protected void AddValidator(BaseValidator validator)
        {
            //注册
            validator.CssClass = "errormessage";
            validator.Display = this.ValidatorDisplay;
            validator.ValidationGroup = this.ValidatorGroup;
            this.OnAddValidator(this.ParentWrap, validator);
            ParentWrap.Controls.Add(validator);
        }


        protected void AddValidator(ExtenderControlBase validator)
        {
            this.OnAddValidator(this.ParentWrap, validator);
            ParentWrap.Controls.Add(validator);
        }

        protected virtual void OnAddValidator(Panel panelParent, BaseValidator validator)
        {
        }

        protected virtual void OnAddValidator(Panel panelParent, ExtenderControlBase validator)
        {
        }

       



        private void AddHelpMessage()
        {
            string helpMessage = this.GetHelpMessage();
            if (!string.IsNullOrEmpty(helpMessage.Trim()))
            {
                Label msg = new Label() { EnableViewState = false, Text = this.GetHelpMessage(), CssClass = "helpmessage" };
                msg.ID = "help_" + this.ID;
                //msg.Style.Add("display","none");

                ParentWrap.Controls.Add(msg);


                ScriptManager.RegisterStartupScript(this, this.GetType(), this.ClientID + "_help_message", string.Format("evlon.facade.textbox.help_message.add('{0}','{1}');", this.ClientID, msg.ClientID), true);
                ScriptManager.RegisterStartupScript(this.Page, this.Page.GetType(), "error_message", "evlon.facade.textbox.clearErrorMessageStyle();", true);
            }
        }


        protected virtual void BuildValidatorControls()
        {

            if ((this.Options & TextBoxOptions.Required) == TextBoxOptions.Required)
            {
                RequiredFieldValidator rfv = new RequiredFieldValidator();
                rfv.ID = "rfv_" + this.ID;
                rfv.ControlToValidate = this.ID;
                rfv.ErrorMessage = "*";// = string.Format("应该输入{0}", this.DisplayName);
                

                //添加到上下文 
                this.AddValidator(rfv);
            }

            this.AddHelpMessage();

            if ((this.Options & TextBoxOptions.Filtered) == TextBoxOptions.Filtered)
            {
                FilteredTextBoxExtender fte = new FilteredTextBoxExtender();
                fte.ID = "fte_" + this.ID;
                fte.TargetControlID = this.ID;
                fte.ValidChars = this.ValidChars;
                fte.InvalidChars = this.InvalidChars;

                fte.FilterType = this.FilterType;

                //添加控件
                this.AddValidator(fte);
            }
        }

        private void Page_LoadComplete(object sender, EventArgs e)
        {
            this.BuildValidatorControls();
        }



        


        private void AppendCssClass(string className)
        {
            this.CssClass = (this.CssClass + " " + className).TrimStart(' ');
        }

        protected override void OnPreRender(EventArgs e)
        {
            BaseTextBoxContext.Current.AddPagePreRender(new EventHandler(EnableValidatorControls));
            preRendered = true;
            base.OnPreRender(e);

            if (this.TextMode == TextBoxMode.MultiLine)
            {
                this.AppendCssClass("textarea");
            }
            else
            {
                if (this.MaxLength > 50)
                {
                    this.AppendCssClass("string_long");
                }
                else
                {
                    this.AppendCssClass("string_short");
                }
            }
        }


    }

    public abstract class NumberTextBox<T> : BaseTextBox where T : IComparable<T>
    {
        private T minValue = default(T);

        public virtual T MinValue
        {
            get { return minValue; }
            set { minValue = value; }
        }
        private T maxValue = default(T);

        public virtual T MaxValue
        {
            get { return maxValue; }
            set { maxValue = value; }
        }

        protected abstract T DefaultMinValue { get; }
        protected abstract T DefaultMaxValue { get; }



        protected ValidationDataType type;
        public virtual ValidationDataType Type
        {
            get { return type; }
            set { type = value; }
        }


        public NumberTextBox()
        {
            this.FilterType = FilterTypes.Numbers;
            this.Options = TextBoxOptions.Required | TextBoxOptions.Filtered;
            this.MaxValue = this.DefaultMaxValue;
            this.MinValue = this.DefaultMinValue;
        }

        protected override void BuildValidatorControls()
        {
            base.BuildValidatorControls();

            //添加额外的控件
            if ((this.MinValue.CompareTo(this.DefaultMinValue) != 0) && (this.MaxValue.CompareTo(this.DefaultMaxValue) != 0))
            {
                RangeValidator rv = new RangeValidator();
                rv.ID = "rv_" + this.ID;
                rv.ControlToValidate = this.ID;
                rv.MaximumValue = this.MaxValue.ToString();
                rv.MinimumValue = this.MinValue.ToString();
                rv.SetFocusOnError = true;
                rv.Type = this.Type;

                rv.ErrorMessage = string.Format("{0}的值应该位于{1}和{2}之间", this.DisplayName, this.MinValue, this.MaxValue);

                this.AddValidator(rv);
            }
            else if (this.MinValue.CompareTo(this.DefaultMinValue) != 0)
            {
                CompareValidator cv = new CompareValidator();
                cv.ID = "rv_" + this.ID;
                cv.ControlToValidate = this.ID;
                cv.SetFocusOnError = true;
                cv.Type = this.Type;
                cv.Operator = ValidationCompareOperator.GreaterThanEqual;



                cv.ValueToCompare = this.MinValue.ToString();
                cv.ErrorMessage = string.Format("{0}的值应该大于{1}", this.DisplayName, this.MinValue);
                this.AddValidator(cv);
            }
            else if ((this.MaxValue.CompareTo(this.DefaultMaxValue) != 0))
            {
                CompareValidator cv = new CompareValidator();
                cv.ID = "rv_" + this.ID;
                cv.ControlToValidate = this.ID;
                cv.SetFocusOnError = true;
                cv.Type = this.Type;

                cv.Operator = ValidationCompareOperator.LessThanEqual;

                cv.ValueToCompare = this.MaxValue.ToString();
                cv.ErrorMessage = string.Format("{0}的值应该小于{1}", this.DisplayName, this.MaxValue);


                this.AddValidator(cv);
            }
            


        }
    }

    public class NumberTextBox : NumberTextBox<int>
    {
        public NumberTextBox()
        {
            this.Type = ValidationDataType.Integer;
        }


        protected override int DefaultMinValue
        {
            get { return int.MinValue; }
        }

        protected override int DefaultMaxValue
        {
            get { return int.MaxValue; }
        }
    }


    public class MoneyTextBox : NumberTextBox<decimal>
    {
        public MoneyTextBox()
        {
            this.Type = ValidationDataType.Currency;
        }
       protected override decimal DefaultMinValue
        {
            get { return decimal.MinValue; }
        }

        protected override decimal DefaultMaxValue
        {
            get { return decimal.MaxValue; }
        }
    }

    public class RegexTextBox : BaseTextBox
    {
        private string regexMatch = string.Empty;

        public virtual string ValidationExpression
        {
            get { return regexMatch; }
            set { regexMatch = value; }
        }





        protected override void BuildValidatorControls()
        {
            base.BuildValidatorControls();

            //添加额外的控件
            if (!string.IsNullOrEmpty(this.ValidationExpression))
            {
                RegularExpressionValidator rev = new RegularExpressionValidator();

                rev.ID = "rv_" + this.ID;
                rev.ControlToValidate = this.ID;
                rev.ValidationExpression = this.ValidationExpression;
                rev.SetFocusOnError = true;

                rev.ErrorMessage = string.Format("{0}的值格式不正确!{1}",this.DisplayName, GetExampleString());

                this.AddValidator(rev);
            }



        }
    }

    public class StringTextBox : RegexTextBox
    {

    }



    public class EMailTextBox : RegexTextBox
    {
        public EMailTextBox()
        {
            this.ValidationExpression = @"^\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*$";
        }
    }

    [Flags]
    public enum PhoneTypes
    { 
        /// <summary>
        /// 手机
        /// </summary>
        Mobile = 1,
        /// <summary>
        /// 小灵通
        /// </summary>
        Unicom = 2,
        /// <summary>
        /// 电话
        /// </summary>
        Phone = 4
    }

    public class PhoneTextBox : RegexTextBox
    {
        private PhoneTypes phoneTypes = PhoneTypes.Phone;

        /// <summary>
        /// 电话类型
        /// </summary>
        public PhoneTypes PhoneTypes
        {
            get { return phoneTypes; }
            set { phoneTypes = value; }
        }

        public override string ValidationExpression
        {
            get
            {
                if (!string.IsNullOrEmpty(base.ValidationExpression))
                {
                    return base.ValidationExpression;
                }
                else
                {
                    StringBuilder sb = new StringBuilder();
                    if ((this.PhoneTypes & PhoneTypes.Phone) == PhoneTypes.Phone)
                    {
                        if (sb.Length > 0)
                            sb.Append("|");
                        sb.Append(@"(^\d{3,4}-\d{7,8}$)");
                    }
                    if ((this.PhoneTypes & PhoneTypes.Mobile) == PhoneTypes.Mobile)
                    {
                        if (sb.Length > 0)
                            sb.Append("|");
                        sb.Append(@"(^1[35]\d{9}$)");
                    }
                    if ((this.PhoneTypes & PhoneTypes.Unicom) == PhoneTypes.Unicom)
                    {
                        if (sb.Length > 0)
                            sb.Append("|");
                        sb.Append(@"(^\d{3,4}-\d{7,8}$)");
                    }

                    return sb.ToString();
                }
            }
            set
            {
                base.ValidationExpression = value;
            }
        }

    }

差不多就这样了，如果有问题请留言。