Question

我有一个动态生成的现有表，该行包含一组控件，如文本框和再次动态生成的下拉列表。主页面上有一个“添加新行”按钮。单击该按钮时，会在表中添加一个新的空白行，并设置所有先前的条目。

当我们点击按钮时出现问题，它会导致主窗体刷新，有没有办法防止这种情况发生？

Answer 1

您必须使用UpdatePanel / Ajax才能在没有完整页面刷新的情况下完成此工作。这answer非常好。

Answer 2

此处的.aspx文件代码：

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="step_by_step.aspx.cs" Inherits="Test_ankit_27Oct_Research_step_by_step" %>
<!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></title>
<style type="text/css">
    #form1
    {
        height: 199px;
    }
</style>
</head>
<body>
<form id="form1" runat="server">
<div>
    <asp:ScriptManager ID="ScriptManager1" runat="server">
    </asp:ScriptManager>
    <br />
    <asp:Button ID="Button2" runat="server" onclick="Button2_Click" 
        Text="Outside Update Button (+2)" />
    <br />
    <asp:UpdatePanel ID="UpdatePanel1" runat="server">
        <ContentTemplate>
            &nbsp;<asp:Button ID="Button1" runat="server" onclick="Button1_Click" 
                Text="Inside Update  Button (+1)" />
            <br />
            &nbsp;
            <asp:Label ID="Label1" runat="server" Font-Bold="True" Text="Label"></asp:Label>
            &nbsp;<br /> &nbsp;
            <asp:Label ID="Label2" runat="server" style="font-weight: 700" Text="Label"></asp:Label>
            <br /> &nbsp;<asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
            <br />
            &nbsp;
            <br />
            &nbsp;
            <br />
        </ContentTemplate>
        <Triggers>
            <asp:AsyncPostBackTrigger ControlID="Button2" EventName="Click" />
        </Triggers>

    </asp:UpdatePanel>
</div>
</form>

此处的.cs文件代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class Test_ankit_27Oct_Research_step_by_step : System.Web.UI.Page
{
    static int start_number_rows = 1; //initial counter default row as 1
    static int counter = start_number_rows;
    protected void Page_Init(object sender, EventArgs e)
   {
       ViewState["RowsCount"] = start_number_rows;
       Label1.Text = "Total Rows : "+counter.ToString();

  }
protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        generate_table();
    }
    else
    {
        //the below part of the code is required to distinguish between autopost back of textbox 
        //and the autopost back of button controls

        string CtrlID = string.Empty;
        if (Request.Form["__EVENTTARGET"] != null &&
                 Request.Form["__EVENTTARGET"] != string.Empty)
        {

             generate_table();
             // for all postbacks except external and internal clicks

        }
        else
        {


            //to check which button or image button click caused the postback
            foreach (string controlID in Request.Form)
            {
                Control objControl = Page.FindControl(controlID);
                if (objControl is Button)
                {
                    CtrlID = objControl.ID;
                    if (CtrlID == "Button1")
                    {

                        //now the call will go to Button1_Click function


                    }
                    if (CtrlID == "Button2")
                    {

                        //now the call will go to Button2_Click function


                    }
                }
            }
        }
       //then let the control flow to button click events
    }
}
protected void generate_table()
{

    Table table = new Table();
    TableRow row;
    TableCell cell;
    TextBox tb;
    table.ID = "Table1";

    int s_rows = Convert.ToInt32(ViewState["RowsCount"].ToString());

    for (int k = 1; k <= s_rows; k++)
    {
        row = new TableRow();
        cell = new TableCell();

        tb = new TextBox();
        tb.ID = "tb_" + k;
        tb.TextChanged += new EventHandler(tb_TextChanged);
        tb.AutoPostBack = true;
        cell.Controls.Add(tb);

        row.Cells.Add(cell);
        table.Rows.Add(row);
    }

   PlaceHolder1.Controls.Add(table);
}

protected void setdata()
{
    Table table = (Table)Page.FindControl("Table1");
    if (table != null)
    {

        foreach (TableRow tr in table.Rows)
        {
            foreach (TableCell tc in tr.Cells)
            {
                foreach (Control ct in tc.Controls)
                {
                    if (ct is TextBox)
                    {

                        ((TextBox)ct).Text = Request.Form[ct.ID];
                    }
                    if (ct is DropDownList)
                    {
                        ((DropDownList)ct).Text = Request.Form[ct.ID];
                    }
                }
            }
        }
    }
}


protected void Button1_Click(object sender, EventArgs e)
{

    counter++;
    Label1.Text = "Total Rows : "+counter.ToString();
    //Label1.Text = "Refreshed at " + DateTime.Now.ToString();

    int new_rows_count = Convert.ToInt32(ViewState["RowsCount"]) + 1; //add one rows at a time
    ViewState["RowsCount"] = new_rows_count;
    generate_table();
    setdata();        //set the values of any of the previously generated  controls
}
protected void Button2_Click(object sender, EventArgs e)
{


     counter=counter+2;
     Label1.Text = "Total Rows : " + counter.ToString();
    //Label1.Text = "Refreshed at " + DateTime.Now.ToString();

    int new_rows_count = Convert.ToInt32(ViewState["RowsCount"]) + 2; //add 2 rows at a time
    ViewState["RowsCount"] = new_rows_count;

    generate_table();
    setdata();        //set the values of any of the previously generated  controls
}

protected void tb_TextChanged(object sender, EventArgs e)
{

    TextBox tb = (TextBox)sender;
    Label2.Text = "Text of textbox "+ tb.ID+ " changed to " + tb.Text;

}
}

如何使用添加按钮动态地向现有表添加行并且在asp.net中没有刷新页面？

2 个答案: