两个DropDownList在Repeater、DataList、DataGrid内的连动和冒泡事件(BubbleEvent) 问题 - DotNet男孩社区-AspxBoy.Com-提供大量.Net技术文章,DotNet技术讨论区

两个DropDownList在Repeater、DataList、DataGrid内的连动和冒泡事件(BubbleEvent) 问题

两个DropDownList在
Repeater、DataList、DataGrid
内的连动和冒泡事件(BubbleEvent) 问题 http://community.csdn.net/Expert/topic/4670/4670056.xml?temp=3.944033E-02
刚看第一眼觉得在第一个DDL的SelectedIndexChanged
事件内绑定第二个DDL就ok了，页
面上写或者ItemDataBound内写都可以打开VS写测试
却发现有点障碍哦，
~~在SelectedIndexChanged内要知道去绑定哪个行哪个列的DDL要费些周折~~。
只有一级一级的向上找Parent最后找到DataGridItem在利用其ItemIndex定位到行在FindControl到要绑定的DDL，终于可以实现，
但比较累。随又想到DataGrid的ItemCommand事件，
但发现WebControl内只有Button ImageButton LinkButton有CommandName和 CommandArgument，可以将事件上浮（冒泡）.
DropDownList先天不足！真是郁闷~~~~~ 能不能自己改造呢，
动手试试就知道了。

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using System;
using System.ComponentModel;
using System.Web.UI.WebControls;

namespace AspxBoy.WebTest.MyControls
{
/// <summary>
/// CommandableDropDownList 的摘要说明。
/// </summary>
public class CommandableDropDownList : DropDownList
{
#region 字段

#endregion

#region 属性

[
Browsable(true),
DefaultValue("")
]
public string CommandName
{
get
{
 return ViewState["CommandName"] == null ? String.Empty : ViewState["CommandName"].ToString();
}
set
{
ViewState["CommandName"] = value;
}
}

[
Browsable(true),
DefaultValue("")
]
public string CommandArgument
{
get
{
return ViewState["CommandArgument"] == null ? String.Empty : ViewState["CommandArgument"].ToString();
}
set
{
ViewState["CommandArgument"] = value;
}
}

#endregion

#region 构造器
public CommandableDropDownList()
{
//
// TODO: 在此处添加构造函数逻辑
//
}
#endregion

#region 事件

private static object _commandEvent = new object();

public event CommandEventHandler SelectedChangedCommand
{
add
{
Events.AddHandler(_commandEvent,value);
}
remove
{
Events.RemoveHandler(_commandEvent,value);
}
}

protected virtual void OnCommand(CommandEventArgs e)
{
CommandEventHandler commandHander = (CommandEventHandler)Events[_commandEvent];
if(commandHander != null)
{
commandHander(this,e);
}
else
{
base.RaiseBubbleEvent(this,e);
}
}

#endregion
 
#region 覆写的方法

protected override void OnSelectedIndexChanged(EventArgs e)
{
base.OnSelectedIndexChanged (e);
if(this.AutoPostBack)
{
CommandEventArgs args = new CommandEventArgs(this.CommandName, this.CommandArgument);
OnCommand(args); 
}
}

#endregion 
}
}

就这样了，然后在模板列内放置该控件，DataGrid的ItemCommand事件内就可以处理到CommandName为你指定的值的操作拉
后台代码如下：

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using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using AspxBoy.WebTest.MyControls;

namespace AspxBoy.WebTest
{
/// <summary>
/// TwoDropDownListInDataGridEx 的摘要说明。
/// </summary>
public class TwoDropDownListInDataGridEx : System.Web.UI.Page
{
protected System.Web.UI.WebControls.DataGrid dg;

private void Page_Load(object sender, System.EventArgs e)
{
// 在此处放置用户代码以初始化页面
if(!Page.IsPostBack)
{
BindGrid();
}
}

private void BindGrid()
{
dg.DataSource =  new string[]{"a","a","a","a","a","a"};
dg.DataBind();
}

#region Web 窗体设计器生成的代码
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
//
InitializeComponent();
base.OnInit(e);
}

/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void InitializeComponent()
{    
this.dg.ItemCommand += new System.Web.UI.WebControls.DataGridCommandEventHandler(this.dg_ItemCommand);
this.dg.ItemDataBound += new System.Web.UI.WebControls.DataGridItemEventHandler(this.dg_ItemDataBound);
this.Load += new System.EventHandler(this.Page_Load);

}
#endregion

private ICollection GetProvinceCollection()
{
return  new string[]{"陕西","辽宁"};
}

private ICollection GetCityCollection(string provinceName)
{
if(provinceName == "陕西")
{
return new string[]{"西安","宝鸡","渭南","汉中"};
}
else if(provinceName == "辽宁")
{
return new string[]{"沈阳","鞍山","抚顺","本溪"};
}
else
{
return null;
}
}

private void dg_ItemDataBound(object sender, System.Web.UI.WebControls.DataGridItemEventArgs e)
{
if(e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.Item)
{
Label lbl = e.Item.FindControl("lbl_no") as Label;
if( lbl != null )
{
lbl.Text = (e.Item.ItemIndex + 1).ToString();
}
CommandableDropDownList ddl_province = e.Item.FindControl("ddl_province") as CommandableDropDownList;
if(ddl_province != null)
{        
ddl_province.DataSource = GetProvinceCollection();
ddl_province.DataBind();
}

CommandableDropDownList ddl_city = e.Item.FindControl("ddl_city") as CommandableDropDownList;
if(ddl_city != null)
{        
ddl_city.DataSource = GetCityCollection(ddl_province.SelectedValue);
ddl_city.DataBind();
}
}
}

private void dg_ItemCommand(object source, System.Web.UI.WebControls.DataGridCommandEventArgs e)
{
if(e.CommandName == "ProvinceChange")
{
string currentProvinceName = String.Empty;
int index = e.Item.ItemIndex;
CommandableDropDownList ddl = this.dg.Items[index].FindControl("ddl_province") as CommandableDropDownList;
if(ddl != null)
{
currentProvinceName = ddl.SelectedValue;
}
ddl = this.dg.Items[index].FindControl("ddl_city") as CommandableDropDownList;
if(ddl != null)
{
ICollection cityCollection = GetCityCollection(currentProvinceName);
if(cityCollection != null)
{
ddl.DataSource = cityCollection;
ddl.DataBind();
}

}
}
}
}
}

aspx代码如下

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<%@ Page language="c#" Codebehind="TwoDropDownListInDataGridEx.aspx.cs" AutoEventWireup="false" Inherits="AspxBoy.WebTest.TwoDropDownListInDataGridEx" %>
<%@ Register TagPrefix="cc1" Namespace="AspxBoy.WebTest.MyControls" Assembly="AspxBoy.WebTest" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<HTML>
<HEAD>
<title>TwoDropDownListInDataGridEx</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="Form1" method="post" runat="server">
<asp:DataGrid id="dg" style="Z-INDEX: 101; LEFT: 112px; POSITION: absolute; TOP: 80px" runat="server"
Width="416px" AutoGenerateColumns="False" Height="16px">
<Columns>
<asp:TemplateColumn HeaderText="NO.">
<ItemTemplate>
<asp:Label runat="server" id="lbl_no"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="Province" FooterText="Province">
<ItemTemplate>
<cc1:CommandableDropDownList id="ddl_province" runat="server" AutoPostBack="true" CommandName="ProvinceChange"></cc1:CommandableDropDownList>
</ItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="City" FooterText="City">
<ItemTemplate>
<cc1:CommandableDropDownList id="ddl_city" runat="server"></cc1:CommandableDropDownList>
</ItemTemplate>
</asp:TemplateColumn>
</Columns>
</asp:DataGrid>
</form>
</body>
</HTML>

若不使用自定义控件，的代码如下（比较累哦

）：

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namespace AspxBoy.WebTest
{
/// <summary>
/// TwoDropDownListInDataGrid 的摘要说明。
/// </summary>
public class TwoDropDownListInDataGrid : System.Web.UI.Page
{
protected System.Web.UI.WebControls.DataGrid dg;

private void Page_Load(object sender, System.EventArgs e)
{
// 在此处放置用户代码以初始化页面
if(!Page.IsPostBack)
{
BindGrid();
}
}

private void BindGrid()
{
dg.DataSource =  new string[]{"a","a","a","a","a","a"};
dg.DataBind();
}

private ICollection GetProvinceCollection()
{
return  new string[]{"陕西","辽宁"};
}

/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void InitializeComponent()
{    
this.dg.ItemCreated += new System.Web.UI.WebControls.DataGridItemEventHandler(this.dg_ItemCreated);
this.dg.ItemDataBound += new System.Web.UI.WebControls.DataGridItemEventHandler(this.dg_ItemDataBound);
this.Load += new System.EventHandler(this.Page_Load);

}
#endregion

private void dg_ItemDataBound(object sender, System.Web.UI.WebControls.DataGridItemEventArgs e)
{
if(e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.Item)
{
Label lbl = e.Item.FindControl("lbl_no") as Label;
if( lbl != null )
{
lbl.Text = (e.Item.ItemIndex + 1).ToString();
}
DropDownList ddl_province = e.Item.FindControl("ddl_province") as DropDownList;
if(ddl_province != null)
{        
ddl_province.DataSource = GetProvinceCollection();
ddl_province.DataBind();
}

DropDownList ddl_city = e.Item.FindControl("ddl_city") as DropDownList;
if(ddl_city != null)
{        
ddl_city.DataSource = GetCityCollection(ddl_province.SelectedValue);
ddl_city.DataBind();
}
}
}

private void dg_ItemCreated(object sender, System.Web.UI.WebControls.DataGridItemEventArgs e)
{
if(e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.Item)
{

DropDownList ddl = e.Item.FindControl("ddl_province") as DropDownList;
if(ddl != null)
{
ddl.AutoPostBack = true; 
ddl.SelectedIndexChanged += new EventHandler(ddl_SelectedIndexChanged);    
}
}
}
protected void ddl_SelectedIndexChanged(object o , EventArgs e)
{
DropDownList ddl = o as DropDownList;

if(ddl != null)
{
TableCell cell =  ddl.Parent as TableCell;
if(cell != null)
{
DataGridItem dgItem = cell.Parent as DataGridItem;  
if(dgItem != null)
{   
string currentProvinceName = String.Empty;
int index = dgItem.ItemIndex;
ddl = this.dg.Items[index].FindControl("ddl_province") as DropDownList;
if(ddl != null)
{
currentProvinceName = ddl.SelectedValue;
}
ddl = this.dg.Items[index].FindControl("ddl_city") as DropDownList;
if(ddl != null)
{
ICollection cityCollection = GetCityCollection(currentProvinceName);
if(cityCollection != null)
{
ddl.DataSource = cityCollection;
ddl.DataBind();
}

}
}
}
}
}
}
}

aspx代码如下

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<%@ Page language="c#" Codebehind="TwoDropDownListInDataGrid.aspx.cs" AutoEventWireup="false" Inherits="AspxBoy.WebTest.TwoDropDownListInDataGrid" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<HTML>
<HEAD>
<title>TwoDropDownListInDataGrid</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="Form1" method="post" runat="server">
<asp:DataGrid id="dg" style="Z-INDEX: 101; LEFT: 112px; POSITION: absolute; TOP: 80px" runat="server"
Width="416px" AutoGenerateColumns="False" Height="16px">
<Columns>
<asp:TemplateColumn HeaderText="NO.">
<ItemTemplate>
<asp:Label runat="server" id="lbl_no"></asp:Label>
</ItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="Province" FooterText="Province">
<ItemTemplate>
<asp:DropDownList id="ddl_province" runat="server"></asp:DropDownList>
</ItemTemplate>
</asp:TemplateColumn>
<asp:TemplateColumn HeaderText="City" FooterText="City">
<ItemTemplate>
<asp:DropDownList id="ddl_city" runat="server"></asp:DropDownList>
</ItemTemplate>
</asp:TemplateColumn>
</Columns>
</asp:DataGrid>
</form>
</body>
</HTML>

Add by : Huobazi (2006-4-08:06:08)

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