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/**
* Namespace: System.Web.UI.WebControls
* Class: DropDownList
*
* 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.Collections.Specialized;
using System.Drawing;
using System.Web;
using System.Web.UI;
namespace System.Web.UI.WebControls
{
[ValidationProperty("SelectedItem")]
public class DropDownList : ListControl, IPostBackDataHandler
{
public DropDownList(): base()
{
}
public override Color BorderColor
{
get
{
return BorderColor;
}
set
{
BorderColor = value;
}
}
public override BorderStyle BorderStyle
{
get
{
return BorderStyle;
}
set
{
BorderStyle = value;
}
}
public override Unit BorderWidth
{
get
{
return BorderWidth;
}
set
{
BorderWidth = value;
}
}
public override int SelectedIndex
{
get
{
return SelectedIndex;
}
set
{
SelectedIndex = value;
}
}
public override string ToolTip
{
get
{
return ToolTip;
}
set
{
ToolTip = value;
}
}
protected override void AddAttributesToRender(HtmlTextWriter writer)
{
if(Page != null)
{
Page.VerifyRenderingInServerForm(this);
}
writer.AddAttribute(HtmlTextWriterAttribute.Name, UniqueID);
AddAttributesToRender(writer);
if(AutoPostBack && Page != null)
{
writer.AddAttribute(HtmlTextWriterAttribute.Onchange, Page.GetPostBackClientEvent(this,""));
writer.AddAttribute("language", "javascript");
}
}
protected override ControlCollection CreateControlCollection()
{
return new EmptyControlCollection(this);
}
protected override void RenderContents(HtmlTextWriter writer)
{
if(Items != null)
{
bool selected = false;
foreach(ListItem current in Items)
{
writer.WriteBeginTag("option");
if(current.Selected)
{
if(selected)
{
throw new HttpException(HttpRuntime.FormatResourceString("Cannot_Multiselect_In_DropDownList"));
}
selected = true;
writer.WriteAttribute("selected", "selected", false);
}
writer.WriteAttribute("value", current.Value, true);
writer.Write('>');
HttpUtility.HtmlEncode(current.Text, writer);
writer.WriteEndTag("option");
writer.WriteLine();
}
}
}
bool IPostBackDataHandler.LoadPostData(string postDataKey, NameValueCollection postCollection)
{
string[] vals = postCollection.GetValues(postDataKey);
if(vals != null)
{
int index = Items.FindByValueInternal(vals[0]);
if(index != SelectedIndex)
{
SelectedIndex = index;
return true;
}
}
return false;
}
void IPostBackDataHandler.RaisePostDataChangedEvent()
{
OnSelectedIndexChanged(EventArgs.Empty);
}
}
}
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