Page.FindControl(String) Metod

Definition

Namnområde:
System.Web.UI
Sammansättning:
System.Web.dll

Söker i containern för sidnamngivning efter en serverkontroll med den angivna identifieraren.

public:
 override System::Web::UI::Control ^ FindControl(System::String ^ id);
public override System.Web.UI.Control FindControl(string id);
override this.FindControl : string -> System.Web.UI.Control
Public Overrides Function FindControl (id As String) As Control

Parametrar

id
String

Identifieraren för kontrollen som ska hittas.

Returer

Control

Den angivna kontrollen eller null om den angivna kontrollen inte finns.

Exempel

Följande kodexempel visar hur du använder FindControl metoden för att hitta kontroller i mallar. I det här exemplet definieras två Repeater kontroller. Var och en visar ett annat sätt att fånga Click händelsen för en LinkButton i repeaterobjektmallen.

<%@ 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">

  private class RepeaterObject
  {
    private string _string;

    public RepeaterObject(string label)
    {
      _string = label;
    }

    public string RepeaterLabel
    {
      get { return _string; }
      set { _string = value; }
    }
  }

  protected void Page_Load()
  {
    if (!IsPostBack)
    {
      ArrayList al = new ArrayList();

      al.Add(new RepeaterObject("RepeaterObject1"));
      al.Add(new RepeaterObject("RepeaterObject2"));
      al.Add(new RepeaterObject("RepeaterObject3"));
      Repeater1.DataSource = al;
      Repeater2.DataSource = al;
      DataBind();
    }
  }


  // This occurs for Repeater1 and originates from LinkButton onClick.
  protected void OnMyCommand1(object sender, CommandEventArgs e)
  {
    LinkButton b = sender as LinkButton;
    if (b != null)
    {
      Label c = (Label)b.Parent.FindControl("Label1");
      if (c != null)
      {
        c.Text = "text changed in handler";
        c.ForeColor = System.Drawing.Color.Green;
      }
    }
  }

  // This occurs for Repeater2 and comes from the Repeater onItemCommand.
  protected void OnMyCommand2(object sender, RepeaterCommandEventArgs e)
  {
    Label l = (Label)e.Item.FindControl("Label1");
    if (l != null)
    {
      l.Text = "text changed in handler";
      l.ForeColor = System.Drawing.Color.Red;
    }
  }
</script>

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

    <asp:Panel ID="Panel1" runat="server" >
        This repeater sample shows the bubbled event and FindControl when the repeater item OnCommand event occurs.<br />
        <asp:Repeater ID="Repeater1" runat="server">
            <ItemTemplate>
                <asp:Label runat="server" ID="Label1" Text='<%#Eval("RepeaterLabel")%>' />&nbsp;
                <asp:LinkButton Text="Change" runat="server" OnCommand="OnMyCommand1" /> <br />
            </ItemTemplate>
        </asp:Repeater>
        <hr />

        This repeater shows the bubbled event and FindControl when the repeater OnItemCommand event occurs. <br />
        <asp:Repeater ID="Repeater2" runat="server" OnItemCommand="OnMyCommand2">
            <ItemTemplate>
                <asp:Label runat="server" ID="Label1" Text='<%#Eval("RepeaterLabel")%>' />&nbsp;
                <asp:LinkButton Text="Change" runat="server" /> <br />
            </ItemTemplate>
        </asp:Repeater>
    </asp:Panel>

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

<%@ Page Language="VB" %>

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

<script runat="server">

  Private Class RepeaterObject
    
    Private _string As String
    
    Public Sub New(ByVal label As String)
      _string = label
    End Sub
    
    Public Property RepeaterLabel() As String
      Get
        Return _string
      End Get
      Set(ByVal value As String)
        _string = value
      End Set
    End Property
  
  End Class
    
    
  Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)

    If (Not IsPostBack) Then
    
      Dim al As New ArrayList()
      al.Add(New RepeaterObject("RepeaterObject1"))
      al.Add(New RepeaterObject("RepeaterObject2"))
      al.Add(New RepeaterObject("RepeaterObject3"))
      Repeater1.DataSource = al
      Repeater2.DataSource = al
      DataBind()
    End If
    
  End Sub


  ' This occurs for Repeater1 and originates from LinkButton onClick.
  Protected Sub OnMyCommand1(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.CommandEventArgs)
    Dim b As LinkButton = sender
    If Not (b Is Nothing) Then
      Dim c As Label = CType(b.Parent.FindControl("Label1"), Label)
      If Not (c Is Nothing) Then
        c.Text = "text changed in handler"
        c.ForeColor = System.Drawing.Color.Green
      End If
    End If
    
  End Sub
  
  ' This occurs for Repeater2 and comes from the Repeater onItemCommand.
  Protected Sub OnMyCommand2(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.RepeaterCommandEventArgs)
    Dim l As Label = CType(e.Item.FindControl("Label1"), Label)
    If Not (l Is Nothing) Then
      l.Text = "text changed in handler"
      l.ForeColor = System.Drawing.Color.Red
    End If
  End Sub
  
</script>

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

    <asp:Panel ID="Panel1" runat="server" >
        This repeater sample shows the bubbled event and FindControl when the repeater item OnCommand event occurs.<br />
        <asp:Repeater ID="Repeater1" runat="server">
            <ItemTemplate>
                <asp:Label runat="server" ID="Label1" Text='<%#Eval("RepeaterLabel")%>' />&nbsp;
                <asp:LinkButton ID="LinkButton1" Text="Change" runat="server" OnCommand="OnMyCommand1" /> <br />
            </ItemTemplate>
        </asp:Repeater>
        <hr />

        This repeater shows the bubbled event and FindControl when the repeater OnItemCommand event occurs. <br />
        <asp:Repeater ID="Repeater2" runat="server" OnItemCommand="OnMyCommand2">
            <ItemTemplate>
                <asp:Label runat="server" ID="Label1" Text='<%#Eval("RepeaterLabel")%>' />&nbsp;
                <asp:LinkButton ID="LinkButton2" Text="Change" runat="server" /> <br />
            </ItemTemplate>
        </asp:Repeater>
    </asp:Panel>

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

Kommentarer

Metoden FindControl kan användas för att komma åt en kontroll vars ID inte är tillgänglig vid designtillfället. Metoden söker bara efter sidans omedelbara container eller översta nivå. den söker inte rekursivt efter kontroller i namngivningscontainrar som finns på sidan. Om du vill få åtkomst till kontroller i en underordnad namngivningscontainer anropar du containerns FindControl metod.

Gäller för

Se även