Page.FindControl(String) Page.FindControl(String) Page.FindControl(String) Page.FindControl(String) Method

定義

在頁面命名容器中搜尋具有指定識別項的伺服器控制項。Searches the page naming container for a server control with the specified identifier.

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

參數

id
String String String String

所要尋找的控制項識別項。The identifier for the control to be found.

傳回

指定的控制項,如果指定的控制項不存在,則為 nullThe specified control, or null if the specified control does not exist.

範例

下列程式碼範例示範如何使用FindControl方法來找出範本內的控制項。The following code example demonstrates how to use the FindControl method to locate controls inside templates. 在此範例中,兩個Repeater控制項定義中,每個會顯示不同的方式,來攔截Click事件的LinkButton內中繼器項目範本。In this example, two Repeater controls are defined; each shows a different way to catch the Click event of a LinkButton inside the repeater item template.

<%@ 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>

備註

FindControl方法可用來存取控制其ID不在執行階段。The FindControl method can be used to access a control whose ID is not available at design time. 該方法會搜尋只有頁面的立即進行,或最上層容器;它會在頁面上所包含的命名容器中的控制項不以遞迴方式搜尋。The method searches only the page's immediate, or top-level, container; it does not recursively search for controls in naming containers contained on the page. 若要存取的次級的命名容器中的控制項,呼叫FindControl該容器的方法。To access controls in a subordinate naming container, call the FindControl method of that container.

適用於

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