aspx.cs 文件中变量的范围 [英] Scope of variables in aspx.cs file

问题描述

我正在编写以下代码:

namespace WebApplication5
{
    public partial class WebForm1 : System.Web.UI.Page
    {
        private DataSet dataset1 = new DataSet();
        OleDbDataAdapter adapter;

        public DataSet ds
        {
            get { return dataset1; }
            set { dataset1 = value; }
        }

        protected void Page_Load(object sender, EventArgs e)
        {
        }

        protected void Button1_Click(object sender, EventArgs e)
        {
            OleDbConnection con = new OleDbConnection();
            con.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:UsersjayantDocumentsUser_Details.accdb";
            con.Open();
            adapter = new OleDbDataAdapter("Select * from User_Details",con);
            adapter.Fill(ds);
            GridView1.DataSource = ds;
            GridView1.DataBind();
           //  ds.WriteXml("C:\MyUser_Details.xml"); If I do this here it writes data
            con.Close();
        }

        protected void Button2_Click(object sender, EventArgs e)
        {
            ds.WriteXml("C:\MyUser_Details.xml");
            // no data in xml files, just root tags
        }
    }
}

这里我的 DataSet 变量是全局变量，但是当我单击 button2 时，它不会向输出 XML 文件发送任何数据.你能告诉我为什么吗?或者我应该做哪些修改来执行此操作?

Here my DataSet variable is global but when I am clicking on button2, it sends no data to the Ouput XML file. Can you please tell me why? Or what modifications shall I make to perform this?

谢谢

推荐答案

 protected void Button1_Click(object sender, EventArgs e)
    {
        OleDbConnection con = new OleDbConnection();
        con.ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:UsersjayantDocumentsUser_Details.accdb";
        con.Open();
        adapter = new OleDbDataAdapter("Select * from User_Details",con);
        adapter.Fill(ds);
        GridView1.DataSource = ds;
        Session.Add("Dataset", ds); //Adding Session here
        GridView1.DataBind();
        con.Close();
    }

    protected void Button2_Click(object sender, EventArgs e)
    {
        DataSet ds = (DataSet)Session["Dataset"]; //Retrieving Value from session
        ds.WriteXml("C:\MyUser_Details.xml");
    }

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