M

E

N

U

 

 

ListBox

выбор одного элемента
событие при выборе элемента
динамическое добавление и удаление одного элемента
динамическое удаление нескольких элементов
 
 

выбор одного элемента

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Копировать
  Default.aspx  
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
 
<!DOCTYPE html>
 
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
 <meta charset="utf-8" />
 <title></title>
</head>
<body>
 <form id="form1" runat="server">
  <div>
   <%-- ДОБАВИТЬ АТРИБУТ SelectionMode="Single" --%>
   <asp:ListBox ID="ListBox1" runat="server" SelectionMode="Single">
    <asp:ListItem Value="#FF0000">Red</asp:ListItem>
    <asp:ListItem Value="#00FF00">Green</asp:ListItem>
    <asp:ListItem Value="#0000FF">Blue</asp:ListItem>
   </asp:ListBox>
   &nbsp;&nbsp;&nbsp;
   <asp:Button ID="Button1" runat="server" Text="OK" OnClick="Button1_Click" />
   &nbsp;&nbsp;&nbsp;
   <asp:Button ID="Button2" runat="server" Text="Clear" OnClick="Button2_Click" />
   &nbsp;&nbsp;&nbsp;
   <asp:Label ID="Label1" runat="server" Text=""></asp:Label>
   &nbsp;&nbsp;&nbsp;
   <asp:Label ID="Label2" runat="server" Text=""></asp:Label>
   &nbsp;&nbsp;&nbsp;
   <asp:Label ID="Label3" runat="server" Text=""></asp:Label>
  </div>
 </form>
</body>
</html>
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Копировать
  Default.aspx.cs  
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
 
public partial class _Default : System.Web.UI.Page {
 protected void Page_Load(object sender, EventArgs e) {
 
 }
 protected void Button1_Click(object sender, EventArgs e) {
  Label1.Text = ListBox1.SelectedIndex.ToString();
  Label2.Text = ListBox1.SelectedItem.Text;
  Label3.Text = ListBox1.SelectedItem.Value;
 }
 protected void Button2_Click(object sender, EventArgs e) {
  Label1.Text = string.Empty;
  Label2.Text = string.Empty;
  Label3.Text = string.Empty;
  ListBox1.ClearSelection();
 }
}
 
 

событие при выборе элемента

Добавить атрибут AutoPostBack="true"
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Копировать
  Default.aspx  
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
 
<!DOCTYPE html>
 
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
 <meta charset="utf-8" />
 <title></title>
</head>
<body>
 <form id="form1" runat="server">
  <div>
   <%-- ДОБАВИТЬ АТРИБУТ AutoPostBack="true" --%>
   <asp:ListBox ID="ListBox1" runat="server" SelectionMode="Single" AutoPostBack="true" OnSelectedIndexChanged="ListBox1_SelectedIndexChanged">
    <asp:ListItem Value="#FF0000">Red</asp:ListItem>
    <asp:ListItem Value="#00FF00">Green</asp:ListItem>
    <asp:ListItem Value="#0000FF">Blue</asp:ListItem>
    <asp:ListItem Value="clear">Clear</asp:ListItem>
   </asp:ListBox>
   &nbsp;&nbsp;&nbsp;
   <asp:Label ID="Label1" runat="server" Text=""></asp:Label>
   &nbsp;&nbsp;&nbsp;
   <asp:Label ID="Label2" runat="server" Text=""></asp:Label>
   &nbsp;&nbsp;&nbsp;
   <asp:Label ID="Label3" runat="server" Text=""></asp:Label>
  </div>
 </form>
</body>
</html>
Скрыть

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Копировать
  Default.aspx.cs  
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
 
public partial class _Default : System.Web.UI.Page {
 protected void Page_Load(object sender, EventArgs e) {
 
 }
 protected void ListBox1_SelectedIndexChanged(object sender, EventArgs e) {
  Label1.Text = ListBox1.SelectedIndex.ToString();
  Label2.Text = ListBox1.SelectedItem.Text;
  Label3.Text = ListBox1.SelectedItem.Value;
  if(ListBox1.SelectedItem.Value == "clear") {
   Label1.Text = string.Empty;
   Label2.Text = string.Empty;
   Label3.Text = string.Empty;
   ListBox1.ClearSelection();
  }
 }
}
 
 

динамическое добавление и удаление одного элемента

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Копировать
  Default.aspx  
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
 
<!DOCTYPE html>
 
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
 <meta charset="utf-8" />
 <title></title>
</head>
<body>
 <form id="form1" runat="server">
  <div>
   <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
   &nbsp;&nbsp;
   <asp:Label ID="Label1" runat="server" Text="Add Text"></asp:Label>
   <br />
   <br />
   <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
   &nbsp;&nbsp;
   <asp:Label ID="Label2" runat="server" Text="Add Value"></asp:Label>
   <br />
   <br />
   <asp:Button ID="Button1" runat="server" Text="Add" OnClick="Button1_Click" />
   <br />
   <br />
   <asp:Button ID="Button2" runat="server" Text="Remove" OnClick="Button2_Click" />
   <br />
   <br />
   <br />
   <asp:ListBox ID="ListBox1" runat="server">
    <asp:ListItem Value="#FF0000">Red</asp:ListItem>
   </asp:ListBox>
   &nbsp;&nbsp;&nbsp;
   <asp:Button ID="Button3" runat="server" Text="OK" OnClick="Button3_Click" />
   &nbsp;&nbsp;&nbsp;
   <asp:Button ID="Button4" runat="server" Text="Clear" OnClick="Button4_Click" />
   &nbsp;&nbsp;&nbsp;
   <asp:Label ID="Label3" runat="server" Text=""></asp:Label>
   &nbsp;&nbsp;&nbsp;
   <asp:Label ID="Label4" runat="server" Text=""></asp:Label>
   &nbsp;&nbsp;&nbsp;
   <asp:Label ID="Label5" runat="server" Text=""></asp:Label>
  </div>
 </form>
</body>
</html>
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Копировать
  Default.aspx.cs  
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
 
public partial class _Default : System.Web.UI.Page {
 protected void Page_Load(object sender, EventArgs e) {
 
 }
 //Add
 protected void Button1_Click(object sender, EventArgs e) {
  ListItem item = new ListItem();
  item.Text = TextBox1.Text;
  item.Value = TextBox2.Text;
  ListBox1.Items.Add(item);
 }
 //Remove
 protected void Button2_Click(object sender, EventArgs e) {
  ListItem item = ListBox1.SelectedItem;
  ListBox1.Items.Remove(item);
 }
 //OK
 protected void Button3_Click(object sender, EventArgs e) {
  Label3.Text = ListBox1.SelectedIndex.ToString();
  Label4.Text = ListBox1.SelectedItem.Text;
  Label5.Text = ListBox1.SelectedItem.Value;
 }
 //Clear
 protected void Button4_Click(object sender, EventArgs e) {
  Label3.Text = string.Empty;
  Label4.Text = string.Empty;
  Label5.Text = string.Empty;
  ListBox1.ClearSelection();
 }
}
 
 

динамическое удаление нескольких элементов

Добавить атрибут SelectionMode="Multiple"
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Копировать
  Default.aspx  
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
 
<!DOCTYPE html>
 
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
 <meta charset="utf-8" />
 <title></title>
</head>
<body>
 <form id="form1" runat="server">
  <div>
  <%-- ДОБАВИТЬ АТРИБУТ SelectionMode="Multiple" --%>
   <asp:ListBox ID="ListBox1" runat="server" SelectionMode="Multiple">
    <asp:ListItem Value="#FF0000">Red</asp:ListItem>
    <asp:ListItem Value="#00FF00">Green</asp:ListItem>
    <asp:ListItem Value="#0000FF">Blue</asp:ListItem>
   </asp:ListBox>
   &nbsp;&nbsp;&nbsp;
   <asp:Button ID="Button1" runat="server" Text="OK" OnClick="Button1_Click"/>
   &nbsp;&nbsp;&nbsp;
   <asp:Button ID="Button2" runat="server" Text="Clear" OnClick="Button2_Click"/>
   &nbsp;&nbsp;&nbsp;
   <asp:Button ID="Button3" runat="server" Text="Remove" OnClick="Button3_Click"/>
   &nbsp;&nbsp;&nbsp;
   <asp:Label ID="Label1" runat="server" Text=""></asp:Label>
   &nbsp;&nbsp;&nbsp;
   <asp:Label ID="Label2" runat="server" Text=""></asp:Label>
   &nbsp;&nbsp;&nbsp;
   <asp:Label ID="Label3" runat="server" Text=""></asp:Label>
  </div>
 </form>
</body>
</html>
Скрыть

Показать

Копировать
  Default.aspx.cs  
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
 
public partial class _Default : System.Web.UI.Page {
 protected void Page_Load(object sender, EventArgs e) {
 
 }
 //OK
 protected void Button1_Click(object sender, EventArgs e) {
  Label1.Text = ListBox1.SelectedIndex.ToString();
  Label2.Text = ListBox1.SelectedItem.Text;
  Label3.Text = ListBox1.SelectedItem.Value;
 }
 //Clear
 protected void Button2_Click(object sender, EventArgs e) {
  Label1.Text = string.Empty;
  Label2.Text = string.Empty;
  Label3.Text = string.Empty;
  ListBox1.ClearSelection();
 }
 //Remove
 protected void Button3_Click(object sender, EventArgs e) {
  for(int i = ListBox1.Items.Count - 1; i >= 0; i--) {
   ListItem item = ListBox1.Items[i];
   if(item.Selected) {
    ListBox1.Items.Remove(item);
   }
  }
 }
}