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/**
* Namespace: System.Web.UI.WebControls
* Class: ListBox
*
* Author: Gaurav Vaish
* Maintainer: gvaish@iitk.ac.in
* Contact: <my_scripts2001@yahoo.com>, <gvaish@iitk.ac.in>
* Implementation: yes
* Status: 100%
*
* (C) Gaurav Vaish (2002)
*/
using System;
using System.Drawing;
using System.Collections;
using System.Collections.Specialized;
using System.Globalization;
using System.Web;
using System.Web.UI;
namespace System.Web.UI.WebControls
{
[ValidationProperty("SelectedItem")]
public class ListBox : ListControl, IPostBackDataHandler
{
public ListBox () : base ()
{
}
public override Color BorderColor
{
get { return base.BorderColor; }
set { base.BorderColor = value; }
}
public override BorderStyle BorderStyle
{
get { return base.BorderStyle; }
set { base.BorderStyle = value; }
}
public override Unit BorderWidth
{
get { return base.BorderWidth; }
set { base.BorderWidth = value; }
}
public virtual int Rows
{
get {
object o = ViewState ["Rows"];
return (o == null) ? 4 : (int) o;
}
set {
if (value < 1 || value > 2000)
throw new ArgumentOutOfRangeException ();
ViewState ["Rows"] = value;
}
}
public virtual ListSelectionMode SelectionMode
{
get
{
object o = ViewState ["SelectionMode"];
return (o == null) ? ListSelectionMode.Single : (ListSelectionMode) o;
}
set
{
if (!Enum.IsDefined (typeof (ListSelectionMode), value))
throw new ArgumentException ();
ViewState ["SelectionMode"] = value;
}
}
public override string ToolTip
{
get { return String.Empty; }
set { /* Don't do anything. */ }
}
protected override void AddAttributesToRender (HtmlTextWriter writer)
{
if (Page != null)
Page.VerifyRenderingInServerForm (this);
writer.AddAttribute (HtmlTextWriterAttribute.Name, UniqueID);
base.AddAttributesToRender (writer);
writer.AddAttribute (HtmlTextWriterAttribute.Size,
Rows.ToString (NumberFormatInfo.InvariantInfo));
if (SelectionMode == ListSelectionMode.Multiple)
writer.AddAttribute (HtmlTextWriterAttribute.Multiple, "multiple");
if (AutoPostBack && Page != null){
writer.AddAttribute (HtmlTextWriterAttribute.Onchange,
Page.GetPostBackClientEvent (this, ""));
writer.AddAttribute ("language", "javascript");
}
}
protected override void OnPreRender (EventArgs e)
{
base.OnPreRender (e);
if (Page != null && SelectionMode == ListSelectionMode.Multiple && Enabled)
Page.RegisterRequiresPostBack(this);
}
protected override void RenderContents (HtmlTextWriter writer)
{
bool isMultAllowed = (SelectionMode == ListSelectionMode.Multiple);
bool selMade = false;
foreach (ListItem current in Items){
writer.WriteBeginTag ("option");
if (current.Selected){
if (!isMultAllowed && selMade)
throw new HttpException ("Cannot_MultiSelect_In_Single_Mode");
selMade = true;
writer.WriteAttribute ("selected", "selected");
}
writer.WriteAttribute ("value", current.Value, true);
writer.Write ('>');
writer.Write (HttpUtility.HtmlEncode (current.Text));
writer.WriteEndTag ("option");
writer.WriteLine ();
}
}
bool IPostBackDataHandler.LoadPostData (string postDataKey,
NameValueCollection postCollection)
{
string[] vals = postCollection.GetValues (postDataKey);
bool updated = false;
ArrayList selected = SelectedIndices;
ArrayList final = new ArrayList (vals.Length);
if (vals != null){
if (SelectionMode == ListSelectionMode.Single){
int index = Items.FindByValueInternal (vals [0]);
if (SelectedIndex != index){
SelectedIndex = index;
updated = true;
}
} else {
foreach (string current in vals)
final.Add (Items.FindByValueInternal (current));
if (selected != null && selected.Count == vals.Length){
for (int ctr = 0; ctr < vals.Length; ctr++){
if (((int) final [ctr]) != ((int) selected [ctr])){
updated = true;
break;
}
}
} else {
updated = true;
}
}
if (!updated)
Select (final);
} else {
if (SelectedIndex != -1)
SelectedIndex = -1;
updated = true;
}
return updated;
}
void IPostBackDataHandler.RaisePostDataChangedEvent ()
{
OnSelectedIndexChanged (EventArgs.Empty);
}
}
}
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