FindControl的詳細介紹

標籤：

FindControl 方法和Javascript 中的 getElementById(string) 非常相似。

FindControl的使用方法 Control.FindControl (String)：在當前的命名容器中搜尋帶指定 id

參數的伺服器控制項。

Eg:

 <form id="form1" runat="server">    <div>        <asp:TextBox ID="TextBox1" runat="server">TextBox</asp:TextBox>        <asp:Button ID="Button1" runat="server" Text="Button"OnClick="Button1_Click" />        <br />        <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label></div> </form>

如上段代碼中，我們想定位到TextBox1 就可以用 Page.Control[0].FindControl("form1").FindControl("TextBox1")……

也可以是

 protected void Button1_Click(object sender, EventArgs e)
    {
      //Control c = this.FindControl("TextBox1");
     //TextBox tb= (TextBox)c;
     //FindControl返回的是一個Control類型的控制項，需要強制類型轉化成TextBox類型
      TextBox tb=(TextBox)this.FindControl("TextBox1");
      this.Label1.Text = tb.Text;   

　　}

當TextBox1放到其他控制項裡時：

 <div>               <asp:Panel ID="Panel1" runat="server" Height="50px" ;125px">        <asp:TextBox ID="TextBox1" runat="server">TextBox</asp:TextBox>        <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>        <asp:Button ID="Button1" runat="server" Text="Button"OnClick="Button1_Click" />        </asp:Panel>    </div>

當TextBox1放到Panel裡，似乎沒什麼影響 TextBox tb=(TextBox)this.FindControl

("TextBox1")，當查看生存頁面的HTML代碼是發現，TextBox的ID並沒有改變，所以可以獲得

TextBox1。

當TextBox1放到DataGrid中

<asp:DataGrid ID="dg1" runat="server"OnSelectedIndexChanged="dg1_SelectedIndexChanged">        <Columns>        <asp:TemplateColumn>        <ItemTemplate>        <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>        </ItemTemplate>        </asp:TemplateColumn>            <asp:ButtonColumn CommandName="Select" Text="選擇"></asp:ButtonColumn>        </Columns>        </asp:DataGrid>

 

這時候this.FindControl("TextBox1")==null,無法獲得TextBox1,查看產生頁面HTML發現，頁

面有多個

 

 <input name="dg1$ctl02$TextBox1" type="text" id="dg1_ctl02_TextBox1" /> <input name="dg1$ctl03$TextBox1" type="text" id="dg1_ctl03_TextBox1" />TextBox1隱藏了，給DataGrid添加選擇列，通過以下方法獲得被選擇行的TextBox1    protected void dg1_SelectedIndexChanged(object sender, EventArgs e)    {        Control c = this.dg1.Items[this.dg1.SelectedIndex].FindControl("TextBox1");        //Control c = this.dg1.SelectedItem.FindControl("TextBox1");        TextBox tb = (TextBox)c;        tb.Text = "TextBox";         }  protected void dg1_EditCommand(object source, DataGridCommandEventArgs e)    {        TextBox tb = (TextBox)e.Item.FindControl("TextBox1");        this.Label1.Text = tb.Text.ToString();    }

如果是在DataGrid的頁首和頁尾：

((TextBox)this.dg1.Controls[0].Controls[0].FindControl("TextBoxH")).Text = "Head"; ((TextBox)this.dg1.Controls[0].Controls[this.dg1.Controls[0].Controls.Count -1].FindControl("TextBoxF")).Text = "Footer";TextBox1在Repeater中   <asp:Repeater ID="Repeater1" runat="server" DataSourceID="SqlDataSource1"OnItemCommand="Repeater1_ItemCommand">        <ItemTemplate>        <asp:TextBox ID="TextBox1" runat="server" Text=""></asp:TextBox><%#DataBinder.Eval(Container.DataItem,"ProductName")%><asp:Button ID="btn"OnClick="btn_click" runat="server" Text="dddd" /><br />        </ItemTemplate>        </asp:Repeater>

 

通過按鈕來獲得TextBox1:

    protected void btn_click(object sender, EventArgs e)     {         //獲得按鈕         Button btn = (Button)sender;         TextBox tb = (TextBox)btn.Parent.FindControl("TextBox1");         tb.Text = "Text";     }

或者

  foreach (RepeaterItem item in this.Repeater1.Items)         {             ((TextBox)item.FindControl("TextBox1")).Text = "Text2";         }

自訂控制項裡的TextBox1

<%@ Control Language="C#" AutoEventWireup="true" CodeFile="WebUserControl.ascx.cs"

Inherits="WebUserControl" %> <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>

 引用<uc1:WebUserControl ID="WebUserControl1" runat="server" />

擷取TextBox1:

((TextBox)this.WebUserControl1.FindControl("TextBox1")).Text = "userc";

模板頁訪問頁面TextBox1

        //模板頁的TextBox1         TextBox tbM = (TextBox)this.FindControl("TextBox1");         //頁面中的TextBox1         TextBox tbC = (TextBox)this.FindControl("ContentPlaceHolder1").FindControl

("TextBox1");         tbC.Text = tbM.Text;

頁面使用模板頁的TextBox1

        //模板頁的TextBox1         TextBox tbM = (TextBox)Master.FindControl("TextBox1");         //本頁面的TextBox1         //錯誤的方法：TextBox tbC = (TextBox)this.FindControl("TextBox1");         TextBox tbC = (TextBox)Master.FindControl

("ContentPlaceHolder1").FindControl("TextBox1");         tbM.Text = tbC.Text.ToString();

【參考】http://www.cnblogs.com/12go/archive/2011/11/27/2264853.html

 

FindControl的詳細介紹