cascadingdropdownextender.cs

AJAX 应用 实现页面的无刷新

// (c) Copyright Microsoft Corporation.
// This source is subject to the Microsoft Permissive License.
// See http://www.microsoft.com/resources/sharedsource/licensingbasics/sharedsourcelicenses.mspx.
// All other rights reserved.

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Globalization;
using System.Text.RegularExpressions;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Xml;

#region Assembly Resource Attribute
[assembly: System.Web.UI.WebResource("AjaxControlToolkit.CascadingDropDown.CascadingDropDownBehavior.js", "text/javascript")]
#endregion

namespace AjaxControlToolkit
{
    /// <summary>
    /// CascadingDropDown extender class definition
    /// </summary>
    [Designer("AjaxControlToolkit.CascadingDropDownDesigner, AjaxControlToolkit")]
    [ClientScriptResource("AjaxControlToolkit.CascadingDropDownBehavior", "AjaxControlToolkit.CascadingDropDown.CascadingDropDownBehavior.js")]
    [RequiredScript(typeof(CommonToolkitScripts))]
    [TargetControlType(typeof(DropDownList))]
    [System.Drawing.ToolboxBitmap(typeof(CascadingDropDown), "CascadingDropDown.CascadingDropDown.ico")]
    public class CascadingDropDown : ExtenderControlBase
    {
        /// <summary>
        /// Constructor
        /// </summary>
        public CascadingDropDown()
        {
            ClientStateValuesLoaded += new EventHandler(CascadingDropDown_ClientStateValuesLoaded);
            EnableClientState = true;
        }

        /// <summary>
        /// Optional ID of the parent DropDownList (upon which the contents of this control are based)
        /// </summary>
        [IDReferenceProperty(typeof(DropDownList))]
        [DefaultValue("")]
        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1706:ShortAcronymsShouldBeUppercase", Justification = "Following ASP.NET AJAX pattern")]
        [ExtenderControlProperty()]
        public string ParentControlID
        {
            get { return GetPropertyValue<string>("ParentControlID", ""); }
            set { SetPropertyValue<string>("ParentControlID", value); }
        }

        /// <summary>
        /// Category of this DropDownList (used when communicating with the helper web service)
        /// </summary>
        [RequiredProperty()]
        [DefaultValue("")]
        [ExtenderControlProperty()]
        public string Category
        {
            get { return GetPropertyValue<string>("Category", ""); }
            set { SetPropertyValue<string>("Category", value); }
        }

        /// <summary>
        /// Optional text displayed by a DropDownList the user has not yet touched.
        /// If omitted, first item in the dropdown is selected
        /// </summary>
        [DefaultValue("")]
        [ExtenderControlProperty()]
        public string PromptText
        {
            get { return GetPropertyValue<string>("PromptText", ""); }
            set { SetPropertyValue<string>("PromptText", value); }
        }

        /// <summary>
        /// Optional value for the option displayed by a DropDownList showing the PromptText
        /// </summary>
        [DefaultValue("")]
        [ExtenderControlProperty()]
        public string PromptValue
        {
            get { return GetPropertyValue<string>("PromptValue", ""); }
            set { SetPropertyValue<string>("PromptValue", value); }
        }

        /// <summary>
        /// Optional text for the option displayed when the list is empty
        /// </summary>
        [DefaultValue("")]
        [ExtenderControlProperty()]
        public string EmptyText
        {
            get { return GetPropertyValue<string>("EmptyText", ""); }
            set { SetPropertyValue<string>("EmptyText", value); }
        }

        /// <summary>
        /// Optional value for the option displayed when the list is empty
        /// </summary>
        [DefaultValue("")]
        [ExtenderControlProperty()]
        public string EmptyValue
        {
            get { return GetPropertyValue<string>("EmptyValue", ""); }
            set { SetPropertyValue<string>("EmptyValue", value); }
        }

        /// <summary>
        /// Optional text displayed by a DropDownList when it is loading its data
        /// </summary>
        [DefaultValue("")]
        [ExtenderControlProperty()]
        public string LoadingText
        {
            get { return GetPropertyValue<string>("LoadingText", ""); }
            set { SetPropertyValue<string>("LoadingText", value); }
        }

        /// <summary>
        /// Selected value of the drop down
        /// </summary>
        [DefaultValue("")]
        [ExtenderControlProperty()]
        public string SelectedValue
        {
            get { return ClientState ?? ""; }
            set { ClientState = value; }
        }

        /// <summary>
        /// Path to the helper web service
        /// </summary>        
        [UrlProperty()]
        [ExtenderControlProperty()]
        [TypeConverter(typeof(ServicePathConverter))]
        public string ServicePath
        {
            get { return GetPropertyValue<string>("ServicePath", ""); }
            set { SetPropertyValue<string>("ServicePath", value); }
        }

        /// <summary>
        /// Prevent the service path from being serialized when it's empty
        /// </summary>
        /// <returns>Whether the service path should be serialized</returns>
        private bool ShouldSerializeServicePath()
        {
            return !string.IsNullOrEmpty(ServiceMethod);
        }

        /// <summary>
        /// Name of the web service method
        /// </summary>
        [RequiredProperty()]
        [DefaultValue("")]
        [ExtenderControlProperty()]
        public string ServiceMethod
        {
            get { return GetPropertyValue<string>("ServiceMethod", ""); }
            set { SetPropertyValue<string>("ServiceMethod", value); }
        }

        /// <summary>
        /// User/page specific context provided to an optional overload of the
        /// web method described by ServiceMethod/ServicePath.  If the context
        /// key is used, it should have the same signature with an additional
        /// parameter named contextKey of type string.
        /// </summary>
        [ExtenderControlProperty]
        [ClientPropertyName("contextKey")]
        [DefaultValue(null)]
        public string ContextKey
        {