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HtmlSelect.Multiple Property

  • Reference

Definition

Namespace:
System.Web.UI.HtmlControls
Assembly:
System.Web.dll

Gets or sets a value indicating whether multiple items can be selected concurrently in the HtmlSelect control.

C# 
public bool Multiple { get; set; }

Property Value

Boolean

true if multiple items can be concurrently selected in the HtmlSelect control; otherwise, false. The default value is false.

Examples

The following code example demonstrates how to use the Multiple property to specify whether multiple items can be selected in the HtmlSelect control.

ASP.NET (C#) 
<%@ Page Language="C#" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

      void Button_Click (Object sender, EventArgs e)
      {

         Label1.Text = "You selected:";

         for (int i=0; i<=Select1.Items.Count - 1; i++)
         {
  
            if (Select1.Items[i].Selected)
               Label1.Text += "<br />    -" + Select1.Items[i].Text;      

         }

         Select1.Size = Convert.ToInt32(Select2.Value);

      }

      void Check_Changed (Object sender, EventArgs e)
      {
        
         Select1.Multiple = CheckBox1.Checked;

      }

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title> HtmlSelect Example </title>
</head>
<body>
<form id="form1" runat="server">
   <div>

      <h3> HtmlSelect Example </h3>

      Select item(s) from the list: <br /><br />

      <select id="Select1" 
              multiple="true"
              runat="server">

         <option value="1" selected="selected"> Item 1 </option>
         <option value="2"> Item 2 </option>
         <option value="3"> Item 3 </option>
         <option value="4"> Item 4 </option>
         <option value="5"> Item 5 </option>
         <option value="6"> Item 6 </option>

      </select>

      <hr />

      HtmlSelect Size: <br />

      <select id="Select2" 
              runat="server">

         <option value="1"> 1 </option>
         <option value="2"> 2 </option>
         <option value="3"> 3 </option>
         <option value="4" selected="selected"> 4 </option>
         <option value="5"> 5 </option>
         <option value="6"> 6 </option>

      </select>

        

      <asp:CheckBox id="CheckBox1"
           Text="Enable Multiple Property"
           AutoPostBack="True"
           OnCheckedChanged="Check_Changed"
           Checked="True"
           runat="server"/>

      <br /><br />

      <button id="Button1"
              onserverclick="Button_Click"
              runat="server">

         Submit

      </button>

      <br /><br />

      <asp:Label id="Label1" runat="server"/>

   </div>
</form>
</body>
</html>

Remarks

Use the Multiple property to specify whether multiple items can be concurrently selected in the HtmlSelect control.

By default, the HtmlSelect control is displayed as a drop-down list box. If you allow multiple selections (by setting the Multiple property to true) or specify a height greater than one row (by setting the Size property to a value greater than 1), the control is displayed as a list box.

To determine the selected items in an HtmlSelect control that allows multiple simultaneous selections, iterate through the Items collection and test the ListItem.Selected property of each item.

Huomautus

The multiple attribute is rendered in the HtmlSelect control only if this property is set to true.

Applies to

Tuote Versiot
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1

See also