页面大小导致gridview DataBind错误

发生异常是因为你的GridView还不是PAGE上的控件，而你正在调用DataBind。在对进行数据绑定之前，必须在页面上添加控件。
并且您必须实现PageIndexChanging Event来处理页面更改事件。

还有一件事是你需要从if (!IsPostBack)块中移动你的数据表代码，因为当页面POSTBACK和控件不再在页面上时，当页面被改变或任何POSTBACK事件被触发时，它不会被执行。这是一个工作代码。

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace demogrid
{
    public partial class grid : System.Web.UI.Page
    {
    GridView gvEmployee = new GridView();
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
        }
        DataTable table = new DataTable();
        table.Columns.Add("Dosage", typeof(int));
        table.Columns.Add("Drug", typeof(string));
        table.Columns.Add("Patient", typeof(string));
        table.Columns.Add("Date", typeof(DateTime));
        // Here we add five DataRows.
        table.Rows.Add(25, "Indocin", "David", DateTime.Now);
        table.Rows.Add(50, "Enebrel", "Sam", DateTime.Now);
        table.Rows.Add(10, "Hydralazine", "Christoff", DateTime.Now);
        table.Rows.Add(21, "Combivent", "Janet", DateTime.Now);
        table.Rows.Add(100, "Dilantin", "Melanie", DateTime.Now);
        BindData(table);
    }
    protected void BindData(DataTable dt)
    {
        gvEmployee.AllowPaging = true;
        gvEmployee.PageSize = 2;
        gvEmployee.AutoGenerateColumns = false;
        gvEmployee.PageIndexChanging += gvEmployee_PageIndexChanging;
        if (dt != null)
        {
            for (int i = 0; i < dt.Columns.Count; i++)
            {
                BoundField boundfield = new BoundField();
                boundfield.DataField = dt.Columns[i].ColumnName.ToString();
                boundfield.HeaderText = dt.Columns[i].ColumnName.ToString();
                gvEmployee.Columns.Add(boundfield);
            }
            Panel1.Controls.Add(gvEmployee);
            gvEmployee.DataSource = dt;
            gvEmployee.DataBind();
            gvEmployee.Width = 600;
            gvEmployee.HeaderStyle.CssClass = "header";
            gvEmployee.RowStyle.CssClass = "rowstyle";
        }
    }
    void gvEmployee_PageIndexChanging(object sender, GridViewPageEventArgs e)
    {
        gvEmployee.PageIndex = e.NewPageIndex;
        gvEmployee.DataBind();
    }

}
}

这是因为没有Pager Template被设置为GridView。我已经修改了你的代码，让你开始。首先添加RowDataBound处理程序并设置分页:

    protected void BindData(DataTable dt)
    {
        GridView gvEmployee = new GridView();
        gvEmployee.AllowPaging = true;
        gvEmployee.PageSize = 4;//this Will work now
        gvEmployee.AutoGenerateColumns = false;
        if (dt != null)
        {
            for (int i = 0; i < dt.Columns.Count; i++)
            {
                BoundField boundfield = new BoundField();
                boundfield.DataField = dt.Columns[i].ColumnName.ToString();
                boundfield.HeaderText = dt.Columns[i].ColumnName.ToString();
                gvEmployee.Columns.Add(boundfield);
            }
            gvEmployee.DataSource = dt;
            gvEmployee.RowDataBound += gvEmployee_RowDataBound;
            gvEmployee.PagerTemplate = new MyTemplate();
            gvEmployee.DataBind();
            gvEmployee.Width = 600;
            gvEmployee.HeaderStyle.CssClass = "header";
            gvEmployee.RowStyle.CssClass = "rowstyle";
            Panel1.Controls.Add(gvEmployee);
        }
    }
    void gvEmployee_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        switch (e.Row.RowType)
        {
            case DataControlRowType.DataRow:
                break;
            case DataControlRowType.EmptyDataRow:
                break;
            case DataControlRowType.Footer:
                break;
            case DataControlRowType.Header:
                break;
            case DataControlRowType.Pager:
                //TODO: handle your pager...
                break;
            case DataControlRowType.Separator:
                break;
            default:
                break;
        }
    }

这里是基本的寻呼机控制:

public class MyTemplate : WebControl, ITemplate
{
    public void InstantiateIn(Control container)
    {
        //TODO: create your pager controls...
    }
}