Question

我在asp.net c＃中创建了非常简单的讨论论坛。它是从xml文件加载和插入数据的转发器。从xml文件加载注释通常可以正常工作，但在将新注释插入xml文件后却没有。单击插入按钮后，它会在xml文件中插入新注释，但转发器无法从同一个xml文件加载任何数据。我尝试在点击事件中重新绑定转发器，但它不起作用。

这是我将数据插入XML的代码（使用xmldocument类）。

XmlNode author = doc.SelectSingleNode(string.Format("//author[@id={0}]",Request.QueryString["id"]));
XmlNode comment = doc.CreateNode(XmlNodeType.Element, "comment", "");
XmlNode name = doc.CreateNode(XmlNodeType.Element, "name", "");
name.InnerText = nameTxb.Text.Trim();
XmlNode date = doc.CreateNode(XmlNodeType.Element, "date", "");
date.InnerText = string.Format("{0:D}", DateTime.Now);
XmlNode message = doc.CreateNode(XmlNodeType.Element, "message", "");
message.InnerText = messageTxb.Text.Trim();
comment.AppendChild(name);
comment.AppendChild(date);
comment.AppendChild(message);
author.AppendChild(comment);
doc.Save(Server.MapPath("~/App_Data/discussion.xml"));
nameTxb.Text = "";
messageTxb.Text = "";
Repeater1.DataSourceID = "XmlDataSource1";
Repeater1.DataBind();

XML片段如下所示：

<comment>
  <name>...</name>
  <date>...</date>
  <message>...</message>
</comment>

Answer 1

保存xml后需要设置XmlDataSource1.DataFile，可能还需要设置如下所示的XPath：

doc.Save(Server.MapPath("~/App_Data/discussion.xml"));
nameTxb.Text = "";
messageTxb.Text = "";
XmlDataSource1.DataFile = Server.MapPath("~/App_Data/discussion.xml");
XmlDataSource1.XPath = "root/author[@id='" + Request.QueryString["id"] + "']/comment";//root is the root in discussion.xml

以下是我测试代码的方法：

我在discussion.xml中有以下xml文件App_Data：

<?xml version="1.0" encoding="utf-8"?>
<root>
  <author id="1">
    <comment>
      <name>John Doe</name>
      <date>Wednesday, December 4, 2013</date>
      <message>Test Message</message>
    </comment>
  </author>
</root>

这是我的标记：

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <asp:Repeater ID="Repeater1" runat="server" DataSourceID="XmlDataSource1">
            <ItemTemplate>
              <h3><%# XPath ("name") %></h3>
              <b>Date:</b>
              <%# XPath ("date") %>
          </ItemTemplate>
        </asp:Repeater>
        <asp:XmlDataSource ID="XmlDataSource1" runat="server"
             DataFile="~/App_Data/discussion.xml"
             XPath="root/author[@id='1']/comment">
        </asp:XmlDataSource>
        <asp:TextBox ID="nameTxb" runat="server"></asp:TextBox>
        <asp:TextBox ID="messageTxb" runat="server"></asp:TextBox>
        <asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
    </div>
    </form>
</body>
</html>

在代码隐藏中我有这种方法：

protected void Button1_Click(object sender, EventArgs e)
{

    string auid = String.IsNullOrEmpty(Request.QueryString["id"]) ? "1" : Request.QueryString["id"];

    XmlDocument doc = new XmlDocument();
    doc.Load(Server.MapPath("~/App_Data/discussion.xml"));
    XmlNode author = doc.SelectSingleNode(string.Format("//author[@id={0}]", auid));
    XmlNode comment = doc.CreateNode(XmlNodeType.Element, "comment", "");
    comment.InnerText = messageTxb.Text;
    XmlNode name = doc.CreateNode(XmlNodeType.Element, "name", "");
    name.InnerText = nameTxb.Text.Trim();
    XmlNode date = doc.CreateNode(XmlNodeType.Element, "date", "");
    date.InnerText = string.Format("{0:D}", DateTime.Now);
    XmlNode message = doc.CreateNode(XmlNodeType.Element, "message", "");
    message.InnerText = messageTxb.Text.Trim();
    comment.AppendChild(name);
    comment.AppendChild(date);
    comment.AppendChild(message);
    author.AppendChild(comment);
    doc.Save(Server.MapPath("~/App_Data/discussion.xml"));
    nameTxb.Text = "";
    messageTxb.Text = "";
    XmlDataSource1.DataFile = Server.MapPath("~/App_Data/discussion.xml");
    XmlDataSource1.XPath = "root/author[@id='" + auid + "']/comment";
    Repeater1.DataBind();
}

插入新项目后重复器重新加载

1 个答案: