答案：后台代码：XmlDocument xmldoc;
protected void Page_Load(object sender, EventArgs e)
{}
protected void Button1_Click(object sender, EventArgs e)
{
xmllod();
foreach (XmlNode xnode in xmldoc.SelectSingleNode("UserDataList").ChildNodes)
{
if (xnode.ChildNodes[0].InnerText == TextBox1.Text && xnode.ChildNodes[1].InnerText == TextBox2.Text)
{
Page.ClientScript.RegisterStartupScript(this.GetType(), "", "<script>alert('登陆成功！');</script>");
return;
}
}
Page.ClientScript.RegisterStartupScript(this.GetType(), "", "<script>alert('登陆失败！');</script>");
}
protected void Button3_Click(object sender, EventArgs e)
{
AddUser();
}
protected void xmllod()
{
xmldoc = new XmlDocument();
xmldoc.Load(Server.MapPath("~/xml/UserInfo.xml"));
}
protected void AddUser()
{
xmllod();
XmlNode xml = xmldoc.SelectSingleNode("UserDataList");
XmlElement xmle = xmldoc.CreateElement("user");
XmlElement xmlenode1 = xmldoc.CreateElement("username");
xmlenode1.InnerText = TextBox3.Text;
XmlElement xmlenode2 = xmldoc.CreateElement("password");
xmlenode2.InnerText = TextBox4.Text;xmle.AppendChild(xmlenode1);
xmle.AppendChild(xmlenode2);
xml.AppendChild(xmle);
xmldoc.Save(Server.MapPath("~/xml/UserInfo.xml"));//保存
Page.ClientScript.RegisterStartupScript(this.GetType(), "", "<script>alert('注册成功！');</script>");
}前台：
<body>
<form id="form1" runat="server">
<div>
帐号：<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox><br />
密码：<asp:TextBox ID="TextBox2" runat="server"></asp:TextBox><br />
<asp:Button ID="Button1" runat="server" Text="登陆" onclick="Button1_Click" />
<asp:Button ID="Button2" runat="server" Text="取消" />
<br />
<br />
帐号：<asp:TextBox ID="TextBox3" runat="server"></asp:TextBox>
<br />密码：<asp:TextBox ID="TextBox4" runat="server"></asp:TextBox><br />
<asp:Button ID="Button3" runat="server" Text="注册" onclick="Button3_Click"/>
</div>
</form>
</body>无非就是对dom树的操作,1、逻辑你自己写
2、XML操作使用XmlDocument类，具体随便在网上搜索一下“C# XmlDocument”很多
