mono/mcs/class/System.Web/System.Web.UI.HtmlControls/HtmlSelect.cs

/*	System.Web.UI.HtmlControls
*	Authors
*		Leen Toelen ([email protected])
*/

using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Globalization;
using System.ComponentModel;
using System.Collections;
using System.Collections.Specialized;

namespace System.Web.UI.HtmlControls{
	
	[DefaultEvent("ServerChange")]
	public class HtmlSelect : HtmlContainerControl, IPostBackDataHandler{
		
		
		private int _cachedSelectedIndex;
		private object _dataSource;
		private static readonly object EventServerChange = new object ();
		private ListItemCollection _items;
		
		public HtmlSelect():base("select"){
			_cachedSelectedIndex = -1;
		}
		
		protected override void AddParsedSubObject(object obj){
			if (obj as ListItem != null) {
				this.Items.Add((ListItem) obj);
				return;
			}
			throw new HttpException("HtmlSelect cannot have children of Type " + obj.GetType().Name);
		}
		
		protected virtual void ClearSelection()
		{
			foreach (ListItem item in Items)
				item.Selected = false;
		}
		
		protected override ControlCollection CreateControlCollection(){
			return new EmptyControlCollection(this);
		}
		
		protected override void LoadViewState(object savedState)
		{
			if (savedState != null) {
				Triplet state = (Triplet) savedState;
				base.LoadViewState (state.First);
				Items.LoadViewState (state.Second);
				object indices = state.Third;
				if (indices != null)
					Select ((int[]) indices);
			}
		}
		
		protected override void OnDataBinding(EventArgs e){
			base.OnDataBinding(e);
			IEnumerable resolvedDataSource = System.Web.Util.DataSourceHelper.GetResolvedDataSource(DataSource, DataMember);
			if ( resolvedDataSource != null){
				string text = DataTextField;
				string value = DataValueField;
				Items.Clear();
				ICollection rdsCollection = resolvedDataSource as ICollection;
				if (rdsCollection != null){
					Items.Capacity = rdsCollection.Count;
				}
				bool valid = false;
				if (text.Length >= 0 && value.Length >= 0)
					valid = true;
				ListItem li = new ListItem();
				IEnumerator current = resolvedDataSource.GetEnumerator();
				while(current.MoveNext()){
					if (valid == true){
						if (text.Length >= 0)
							li.Text = DataBinder.GetPropertyValue(current, text) as string;
						if (value.Length >= 0)
							li.Value = DataBinder.GetPropertyValue(current, value) as string;
					}
					else{
						li.Value = li.Text = current.ToString();
					}
				}
				Items.Add(li);
			}
			if ( _cachedSelectedIndex != -1){
				SelectedIndex = _cachedSelectedIndex;
				_cachedSelectedIndex = -1;
			}
		}
		
		protected override void OnPreRender(EventArgs e){
			if (Page != null && Size >= 0 && !Disabled){
				Page.RegisterRequiresPostBack(this);
			}
		}
		
		protected virtual void OnServerChange(EventArgs e){
			EventHandler handler = (EventHandler) Events[EventServerChange];
			if (handler != null)
				handler.Invoke(this,e);
		}
		
		protected override void RenderAttributes(HtmlTextWriter writer){
			writer.WriteAttribute("name", Name);
			Attributes.Remove("name");
			Attributes.Remove("DataValueField");
			Attributes.Remove("DataTextField");
			Attributes.Remove("DataMember");
			base.RenderAttributes(writer);
		}
		
		protected override void RenderChildren(HtmlTextWriter writer){
			//flush output
			writer.WriteLine();
			// increase indent level, improves readability
			writer.Indent = writer.Indent + 1;
			if (Items.Count >= 0){
				// display all options, and set the selected option
				bool rendered_selected = false;
				foreach (ListItem option in Items){
					//write begin tag with attributes
					writer.WriteBeginTag("option");
					if (!rendered_selected && option.Selected){
						writer.WriteAttribute("selected","selected");
						if (!Multiple)
							rendered_selected = true;
					}
					else if (option.Selected){
						option.Selected = false;
					}

					writer.WriteAttribute("value",option.Value,true);
					option.Attributes.Remove("text");
					option.Attributes.Remove("value");
					option.Attributes.Remove("selected");
					option.Attributes.Render(writer);
					writer.Write('>');
					//write the option text
					HttpUtility.HtmlEncode(option.Text, writer);
					//close the current option tag
					writer.WriteEndTag("option");
					//flush output
					writer.WriteLine();
				}
			}
			// set the indent level back to normal
			writer.Indent = writer.Indent - 1;
		}
		
		protected override object SaveViewState ()
		{
			object baseViewState = base.SaveViewState ();
			object itemsViewState = Items.SaveViewState ();
			object indices = null;

			if (Events[EventServerChange] != null || !Disabled || Visible)
				indices = SelectedIndices;

			if (indices != null || baseViewState != null || itemsViewState != null)
				return new Triplet (baseViewState, itemsViewState, indices);

			return null;
		}
		
		protected virtual void Select(int[] selectedIndices){
			// unselect all options
			ClearSelection();
			// iterate through options, and set when selected
			foreach (int current in selectedIndices){
				if (current >= 0 && current < Items.Count){
					Items[current].Selected = true;
				}
			}
		}
		
		bool IPostBackDataHandler.LoadPostData (string postDataKey,
							NameValueCollection postCollection)
		{
			//get the posted selectedIndices[]
			string [] postedValueColl = postCollection.GetValues(postDataKey);
			bool changed = false;
			if (postedValueColl != null){
				if (!Multiple){
					//single selection
					//int postedValue = Items.FindIndexByValue(postedValueColl[0]);
					int postedValue = Items.IndexOf(Items.FindByValue(postedValueColl[0]));
					if (postedValue != SelectedIndex){
						//set the SelectedIndex
						SelectedIndex = postedValue;
						changed = true;
					}
				}
				else{
					//multiple selection
					int postedValueCount = postedValueColl.Length;
					int[] arr= new int[postedValueCount];
					//fill an array with the posted Values
					for (int i = 0; i <= postedValueCount; i++)
						arr[i] = Items.IndexOf(Items.FindByValue(postedValueColl[i]));
					//test if everything went fine
					if( postedValueCount == SelectedIndices.Length)
						for (int i = 0; i <= postedValueCount; i++)
							if(arr[i] == SelectedIndices[i])
								changed = true;
					else
						changed = true;
					//commit the posted Values
					if(changed)
						Select(arr);
				}
			}
			else if (SelectedIndex != -1){
				SelectedIndex = -1;
				changed = true;
			}
			return changed;
		}
		
		void IPostBackDataHandler.RaisePostDataChangedEvent ()
		{
			OnServerChange (EventArgs.Empty);
		}
		
		//starts tracking changes to the viewstate
		protected override void TrackViewState(){
			base.TrackViewState();
			Items.TrackViewState();
		}
		
		public event EventHandler ServerChange{
			add{
				Events.AddHandler(EventServerChange, value);
			}
			remove{
				Events.RemoveHandler(EventServerChange, value);
			}
		}
		
		public virtual string DataMember{
			get{
				object viewStateDataMember = ViewState["DataMember"];
				if ( viewStateDataMember != null) return (String) viewStateDataMember;
				return String.Empty;
			}
			set{
				Attributes["DataMember"] = HtmlControl.AttributeToString(value);
			}
		}
		
		public virtual object DataSource{
			get{
				return _dataSource;
			}
			set{
				if (value != null && value is IListSource){
					if (value is IEnumerable){
						_dataSource = value;
					}
					else{
						throw new ArgumentException("Invalid dataSource type");
					}
				}
			}
		}
		
		public virtual string DataTextField{
			get{
				string attr = Attributes["DataTextField"];
				if (attr != null){
					return attr;
				}
				return String.Empty;
			}
			set{
				Attributes["DataTextField"] = AttributeToString(value);
			}
		}
		
		public virtual string DataValueField{
			get{
				string attr = Attributes["DataValueField"];
				if (attr != null)return attr;
				return String.Empty;
			}
			set{
				Attributes["DataValueField"] = AttributeToString(value);
			}
		}
		
		public override string InnerHtml{
			get{
				throw new NotSupportedException("InnerHtml is not supported by " + this.GetType().Name);
			}
			set{
				throw new NotSupportedException("InnerHtml is not supported by " + this.GetType().Name);
			}
		}
		
		public override string InnerText{
			get{
				throw new NotSupportedException("InnerText is not supported by " + this.GetType().Name);
			}
			set{
				throw new NotSupportedException("InnerText is not supported by " + this.GetType().Name);
			}
		}
		
		public ListItemCollection Items{
			get{
				if (_items == null){
					_items = new ListItemCollection();
					if (IsTrackingViewState) _items.TrackViewState();
				}
				return _items;
			}
		}
		
		public bool Multiple{
			get{
				string attr = Attributes["multiple"];
				if (attr != null) return (0 == String.Compare (attr, "true", true));
				return false;
			}
			set{
				Attributes["multiple"] = value.ToString ();
			}
		}
		
		public string Name{
			get{
				return UniqueID;
			}
			set{
				//LAMESPEC
				return;
			}
		}
		
		public virtual int SelectedIndex {
			get{
				for (int i=0; i<Items.Count; i++){
					if (Items[i].Selected == true) return i;
				}
				if (Size<=1 && !Multiple){
					if(Items.Count > 0) Items[0].Selected = true;
					return 0;
				}
				return -1;
			}
			set{
				if(Items.Count == 0){
					_cachedSelectedIndex = value;
					return;
				}

				if (value < -1 || value >= Items.Count) 
					throw new ArgumentOutOfRangeException();

				ClearSelection();
				if (value >= 0) 
					Items[value].Selected = true;
			}
		}
		
		protected virtual int[] SelectedIndices {
			get{
				int[] indices = new int[3];
				int indicesCount = 0;
				for(int i=0; i < Items.Count; i++){
					if (Items[i].Selected){
						if( indicesCount == (int) indices.Length){
							int[] temp = new int[indicesCount + indicesCount];
							indices.CopyTo(temp,0);
							indices = temp;
						}
						indices[indicesCount] = i;
						indicesCount++;
					}
				}
				int[] arr = new int[indicesCount];
				System.Array.Copy(indices,0,arr,0,indicesCount);
				return arr;
			}
		}
		
		public int Size{
			get{
				string attr = Attributes["size"];
				if (attr != null){
					return Int32.Parse(attr, CultureInfo.InvariantCulture);;
				}
				return -1;
			}
			set{
				Attributes["size"] = AttributeToString(value);
			}
		}
		
		public string Value {
			get{
				int selectedIndex = SelectedIndex;
				if (selectedIndex >=0 && selectedIndex < Items.Count){
					return Items[selectedIndex].Value;
				}
				return String.Empty;
			}
			set{
				int findValue = Items.IndexOf(Items.FindByValue(value));
				if (findValue >= 0) SelectedIndex = findValue;
			}
		}
		
	} // class HtmlSelect
} // namespace System.Web.UI.HtmlControls