(五)ASP.NET中动态生成控件

今天被问到如何在ASP.NET 页面中动态创建一批控件，并且希望在后续代码中能访问到这些动态创建的控件。我用下面的例子来解释这个问题

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页面文件：

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    <asp:Button ID="createbutton" runat="server" Text="批量创建按钮" 
            onclick="createbutton_Click" /><asp:Button ID="displaybutton" 
            runat="server"  Text="显示动态按钮的信息" onclick="displaybutton_Click"/>
    <asp:Table ID="HolderTable"  runat="server"></asp:Table>
    </div>
    </form>
</body>
</html>

----上面的Table是用来存放动态控件的，用Table是因为它有行和列的概念，更易于布局设计。除了Table之外，还可以使用PlaceHolder控件或者Panel控件

代码文件：

public partial class _Default : System.Web.UI.Page
{

    protected override void OnLoad(EventArgs e)
    {
        CreateControl();
    }

    protected void createbutton_Click(object sender, EventArgs e)
    {
        if (ViewState["CreateControl"] == null)
        {
            ViewState["CreateControl"] = true;
            CreateControl();
        }
    }

    void CreateControl() {
        ///批量创建100个按钮
        ///

        if (ViewState["CreateControl"]==null) return; //第一次的时候应该不要创建这些控件

        for (int x = 0; x < 10; x++)
        {
            TableRow row = new TableRow();
            for (int y = 0; y < 10; y++)
            {
                TableCell cell = new TableCell();

                Button bt = new Button();
                bt.Text = string.Format("  x={0},y={1}  ", x, y);
                bt.Click += new EventHandler(bt_Click);
                cell.Controls.Add(bt);

                row.Cells.Add(cell);
            }

            HolderTable.Rows.Add(row);
        }
    }

    void bt_Click(object sender, EventArgs e)
    {
        Trace.Write("控件动态事件");
        ((Button)sender).BackColor = System.Drawing.Color.Red;
        Response.Write(string.Format("你点击了该按钮：{0}", ((Button)sender).Text));
    }

    /// <summary>
    /// 显示动态创建的控件的信息
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void displaybutton_Click(object sender, EventArgs e)
    {
        for (int x = 0; x < 10; x++)
        {
            TableRow row = HolderTable.Rows[x];
            for (int y = 0; y < 10; y++)
            {
                Button bt = (Button)row.Cells[y].Controls[0];
                Response.Write(bt.Text);
            }
        }
    }
}