Question

我引用此网站尝试编写代码 - 在ASP.Net C中的HTML表格中显示DataTable #Webform：http://www.aspsnippets.com/Articles/Display-DataTable-in-HTML-Table-in-ASPNet-using-C-and-VBNet.aspx

但无法显示表格信息，显示空白页面。我该如何修复此代码？谢谢。

1.CS.aspx

 <%@ Page Language="C#" AutoEventWireup="true" CodeFile="CS.aspx.cs" Inherits="CS" %>

<!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">
`body { font-family: Arial;font-size: 10pt; }`

        table {
            border: 1px solid #ccc;
            border-collapse: collapse;
        }

            table th {
                background-color: #F7F7F7;
                color: #333;
                font-weight: bold;
            }

            table th, table td {
                padding: 5px;
                border-color: #ccc;
            }
    </style>
</head>
<body>
    <form id="form1" runat="server">
        <div style="margin-left: auto; margin-right: auto; text-align: center;">

            <asp:PlaceHolder ID="placeholder" runat="server" />

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

2.CS.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Data;
using System.Text;
using System.Configuration;




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

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {
            PlaceHolder placeholder = new PlaceHolder();

            //Populating a DataTable from database.
            DataTable dt = this.GetData();

            //Building an HTML string.
            StringBuilder html = new StringBuilder();

            //Table start.
            html.Append("<table border = '1'>");

            //Building the Header row.
            html.Append("<tr>");
            foreach (DataColumn column in dt.Columns)
            {
                html.Append("<th>");
                html.Append(column.ColumnName);
                html.Append("</th>");
            }
            html.Append("</tr>");

            //Building the Data rows.
            foreach (DataRow row in dt.Rows)
            {
                html.Append("<tr>");
                foreach (DataColumn column in dt.Columns)
                {
                    html.Append("<td>");
                    html.Append(row[column.ColumnName]);
                    html.Append("</td>");
                }
                html.Append("</tr>");
            }

            //Table end.
            html.Append("</table>");
            string strText = html.ToString();

            ////Append the HTML string to Placeholder.
            placeholder.Controls.Add(new Literal { Text = html.ToString() });

        }
    }

    private DataTable GetData()
    {
        string constr = ConfigurationManager.ConnectionStrings["constr"].ConnectionString;
        using (SqlConnection con = new SqlConnection(constr))
        {
            using (SqlCommand cmd = new SqlCommand("SELECT TOP 10 [a01],[a02],[a03] FROM [aaa].[dbo].[bbb]"))
            {
                using (SqlDataAdapter sda = new SqlDataAdapter())
                {
                    cmd.Connection = con;
                    sda.SelectCommand = cmd;
                    using (DataTable dt = new DataTable())
                    {
                        sda.Fill(dt);
                        return dt;
                    }
                }
            }
        }
    }
}

Answer 1

注释掉这一行，它会起作用：

PlaceHolder placeholder = new PlaceHolder();

只是一个想法。而不是手动循环DataTable为什么不使用GridView控件？

代码背后：

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = this.GetData();
        gridView.DataSource = dt;
        gridView.DataBind();
    }
}

ASPX页面

<asp:GridView ID="gridView" runat="server"></asp:GridView>

Answer 2

如果我有分数，我会发表评论但是为了解决你的问题，你需要做的就是注释掉以下一行：

PlaceHolder placeholder = new PlaceHolder();

原因是，您的标记上有一个名为PlaceHolder的{{1}}，然后在加载代码中创建一个全新的placeholder变量placeholder。虽然它们的名称相同，但代码将它们视为完全不同的对象。请参阅下面的代码，我借用其他人的代码来创建PlaceHolder，因为我无法访问您的数据库。

datatable

在ASP.Net C＃Webform中的HTML表格中显示DataTable

2 个答案: