Gridview srno值会增加，但当页面刷新时，其值会再次重置并显示srno=1。如何增值

这是我的主要方法。 受保护的覆盖无效CreateChildControls（） {

    HiddenField HFSN = new HiddenField();
    DataTable table= new DataTable();
    DataTable result=new DataTable();
    private int srno = 1;
    private string headlines;
    private string date;
    Button btn = new Button();

    private const string _ascxPath = @"~/_CONTROLTEMPLATES/GridViewWP/GridView8/VisualWebPart1UserControl.ascx";
    private Microsoft.SharePoint.WebControls.SPGridView _grid;

        btn.Visible = true;
        btn.Text = "Show";
        btn.Click += new EventHandler(btn_Click);
        _grid = new Microsoft.SharePoint.WebControls.SPGridView();
        _grid.AutoGenerateColumns = false;
        _grid.AllowPaging = true;
        _grid.PageSize = 5;
        //_grid.PageIndexChanging += _grid_PageIndexChanging;
       foreach (DataColumn column in table.Columns)
            _grid.Columns.Add(new BoundField()
            {
                DataField = column.ColumnName,
                HeaderText = column.ColumnName
            });
        //_grid.DataSource = table;
        this.Controls.Add(_grid);
       // _grid.PagerTemplate = null;
        //_grid.DataBind();
        _grid.Visible = true;
        this.Controls.Add(btn);
    }

一次性btn单击仅显示一行。每次按下按钮时，它将显示静态添加到GetDataTable（）中的新行。 ******无效btn_单击（对象发送者，事件参数e） {

    HiddenField HFSN = new HiddenField();
    DataTable table= new DataTable();
    DataTable result=new DataTable();
    private int srno = 1;
    private string headlines;
    private string date;
    Button btn = new Button();

    private const string _ascxPath = @"~/_CONTROLTEMPLATES/GridViewWP/GridView8/VisualWebPart1UserControl.ascx";
    private Microsoft.SharePoint.WebControls.SPGridView _grid;

        btn.Visible = true;
        btn.Text = "Show";
        btn.Click += new EventHandler(btn_Click);
        _grid = new Microsoft.SharePoint.WebControls.SPGridView();
        _grid.AutoGenerateColumns = false;
        _grid.AllowPaging = true;
        _grid.PageSize = 5;
        //_grid.PageIndexChanging += _grid_PageIndexChanging;
       foreach (DataColumn column in table.Columns)
            _grid.Columns.Add(new BoundField()
            {
                DataField = column.ColumnName,
                HeaderText = column.ColumnName
            });
        //_grid.DataSource = table;
        this.Controls.Add(_grid);
       // _grid.PagerTemplate = null;
        //_grid.DataBind();
        _grid.Visible = true;
        this.Controls.Add(btn);
    }

srno=Convert.ToInt32（HFSN.Value）；
DataRow[]行=表。选择（）；
如果（srno
使用会话代替私有变量

使用asp.net隐藏控件存储值。您将获得viewstate的好处