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CheckBoxList Konstruktor

  • Referenz

Definition

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

Initialisiert eine neue Instanz der CheckBoxList-Klasse.

public:
 CheckBoxList();
public CheckBoxList ();
Public Sub New ()

Beispiele

Im folgenden Codebeispiel wird veranschaulicht, wie eine neue Instanz des CheckBoxList Steuerelements erstellt und initialisiert wird.

Hinweis

Im folgenden Codebeispiel wird das Einzeldateicodemodell verwendet. Es funktioniert möglicherweise nicht ordnungsgemäß, wenn es direkt in eine CodeBehind-Datei kopiert wird. Dieses Codebeispiel muss in eine leere Textdatei mit einer .aspx-Erweiterung kopiert werden. Weitere Informationen zum Web Forms-Codemodell finden Sie unter ASP.NET Web Forms-Seitencodemodell.


<%@ Page Language="C#" AutoEventWireup="True" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">
    <title> CheckBoxList Constructor Example </title>
<script runat="server">

      void Check_Clicked(Object sender, EventArgs e) 
      {

         // Retrieve the CheckBoxList control from the Controls collection
         // of the PlaceHolder control.
         CheckBoxList checklist = 
             (CheckBoxList)Place.FindControl("checkboxlist1");

         // Make sure a control was found.
         if(checklist != null)
         { 

            Message.Text = "Selected Item(s):<br /><br />";

            // Iterate through the Items collection of the CheckBoxList 
            // control and display the selected items.
            for (int i=0; i<checklist.Items.Count; i++)
            {

               if (checklist.Items[i].Selected)
               {

                  Message.Text += checklist.Items[i].Text + "<br />";

               }

            }

         }

         else
         {

            // Display an error message.
            Message.Text = "Unable to find CheckBoxList control.";

         }

      }

      void Page_Load(Object sender, EventArgs e)
      {

         // Create a new CheckBoxList control.
         CheckBoxList checklist = new CheckBoxList();

         // Set the properties of the control.
         checklist.ID = "checkboxlist1";
         checklist.AutoPostBack = true;
         checklist.CellPadding = 5;
         checklist.CellSpacing = 5;
         checklist.RepeatColumns = 2;
         checklist.RepeatDirection = RepeatDirection.Vertical;
         checklist.RepeatLayout = RepeatLayout.Flow;
         checklist.TextAlign = TextAlign.Right;

         // Populate the CheckBoxList control.
         checklist.Items.Add(new ListItem("Item 1"));
         checklist.Items.Add(new ListItem("Item 2"));
         checklist.Items.Add(new ListItem("Item 3"));
         checklist.Items.Add(new ListItem("Item 4"));
         checklist.Items.Add(new ListItem("Item 5"));
         checklist.Items.Add(new ListItem("Item 6"));

         // Manually register the event-handling method for the 
         // SelectedIndexChanged event.
         checklist.SelectedIndexChanged += new EventHandler(this.Check_Clicked);

         // Add the control to the Controls collection of the 
         // PlaceHolder control.
         Place.Controls.Add(checklist);

      }

   </script>
 
</head>

<body>
   
   <form id="form1" runat="server">
 
      <h3> CheckBoxList Constructor Example </h3>

      Select items from the CheckBoxList.

      <br /><br />

      <asp:PlaceHolder id="Place" runat="server"/>
 
      <br /><br />

      <asp:label id="Message" runat="server"/>
             
   </form>
          
</body>

</html>


<%@ Page Language="VB" AutoEventWireup="True" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >

<head runat="server">
    <title> CheckBoxList Constructor Example </title>
<script runat="server">

      Sub Check_Clicked(sender As Object, e As EventArgs) 

         ' Retrieve the CheckBoxList control from the Controls collection
         ' of the PlaceHolder control.
         Dim checklist As CheckBoxList = _
             CType(Place.FindControl("checkboxlist1"), CheckBoxList)

         ' Make sure a control was found.
         If Not checklist Is Nothing

            Message.Text = "Selected Item(s):<br /><br />"

            ' Iterate through the Items collection of CheckBoxList 
            ' control and display the selected items.
            Dim i As Integer

            For i=0 To checklist.Items.Count - 1

               If checklist.Items(i).Selected Then

                  Message.Text &= checklist.Items(i).Text & "<br />"

               End If

            Next i

         Else

            ' Display an error message.
            Message.Text = "Unable to find CheckBoxList control."

         End If

      End Sub

      Sub Page_Load(sender As Object, e As EventArgs)

         ' Create a new CheckBoxList control.
         Dim checklist As CheckBoxList = New CheckBoxList()

         ' Set the properties of the control.
         checklist.ID = "checkboxlist1"
         checklist.AutoPostBack = True
         checklist.CellPadding = 5
         checklist.CellSpacing = 5
         checklist.RepeatColumns = 2
         checklist.RepeatDirection = RepeatDirection.Vertical
         checklist.RepeatLayout = RepeatLayout.Flow
         checklist.TextAlign = TextAlign.Right

         ' Populate the CheckBoxList control.
         checklist.Items.Add(New ListItem("Item 1"))
         checklist.Items.Add(New ListItem("Item 2"))
         checklist.Items.Add(New ListItem("Item 3"))
         checklist.Items.Add(New ListItem("Item 4"))
         checklist.Items.Add(New ListItem("Item 5"))
         checklist.Items.Add(New ListItem("Item 6"))

         ' Manually register the event-handling method for the 
         ' SelectedIndexChanged event.
         AddHandler checklist.SelectedIndexChanged, AddressOf Check_Clicked

         ' Add the control to the Controls collection of the 
         ' PlaceHolder control.
         Place.Controls.Add(checklist)

      End Sub

   </script>
 
</head>

<body>
   
   <form id="form1" runat="server">
 
      <h3> CheckBoxList Constructor Example </h3>

      Select items from the CheckBoxList.

      <br /><br />

      <asp:PlaceHolder id="Place" runat="server"/>
 
      <br /><br />

      <asp:label id="Message" runat="server"/>
             
   </form>
          
</body>

</html>

Hinweise

Verwenden Sie diesen Konstruktor, um eine neue Instanz der CheckBoxList -Klasse zu erstellen und zu initialisieren.

Gilt für:

Weitere Informationen