大数量查询分页显示微软的解决办法

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我是靠谱客的博主感性彩虹，最近开发中收集的这篇文章主要介绍大数量查询分页显示微软的解决办法，觉得挺不错的，现在分享给大家，希望可以做个参考。

概述

微软的解决办法
using System;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Windows.Forms;

public class PagingSample: Form
{
// Form controls.
Button prevBtn = new Button();
Button nextBtn = new Button();

static DataGrid myGrid = new DataGrid();
static Label pageLbl = new Label();

// Paging variables.
static int pageSize = 10; // Size of viewed page.
static int totalPages = 0; // Total pages.
static int currentPage = 0; // Current page.
static string firstVisibleCustomer = ""; // First customer on page to determine location for move previous.
static string lastVisibleCustomer = ""; // Last customer on page to determine location for move next.

// DataSet to bind to DataGrid.
static DataTable custTable;

// Initialize connection to database and DataAdapter.
static SqlConnection nwindConn = new SqlConnection("Data Source=localhost;Integrated Security=SSPI;Initial Catalog=northwind");
static SqlDataAdapter custDA = new SqlDataAdapter("", nwindConn);
static SqlCommand selCmd = custDA.SelectCommand;

public static void GetData(string direction)
{
// Create SQL statement to return a page of records.
selCmd.Parameters.Clear();

switch (direction)
{
case "Next":
selCmd.CommandText = "SELECT TOP " + pageSize + " CustomerID, CompanyName FROM Customers " +
"WHERE CustomerID > @CustomerId ORDER BY CustomerID";
selCmd.Parameters.Add("@CustomerId", SqlDbType.VarChar, 5).Value = lastVisibleCustomer;
break;
case "Previous":
selCmd.CommandText = "SELECT TOP " + pageSize + " CustomerID, CompanyName FROM Customers " +
"WHERE CustomerID < @CustomerId ORDER BY CustomerID DESC";
selCmd.Parameters.Add("@CustomerId", SqlDbType.VarChar, 5).Value = firstVisibleCustomer;
break;
default:
selCmd.CommandText = "SELECT TOP " + pageSize + " CustomerID, CompanyName FROM Customers ORDER BY CustomerID";

// Determine total pages.
SqlCommand totCMD = new SqlCommand("SELECT Count(*) FROM Customers", nwindConn);
nwindConn.Open();
int totalRecords = (int)totCMD.ExecuteScalar();
nwindConn.Close();
totalPages = (int)Math.Ceiling((double)totalRecords / pageSize);

break;
}

// Fill a temporary table with query results.
DataTable tmpTable = new DataTable("Customers");
int recordsAffected = custDA.Fill(tmpTable);

// If table does not exist, create it.
if (custTable == null)
custTable = tmpTable.Clone();

// Refresh table if at least one record returned.
if (recordsAffected > 0)
{
switch (direction)
{
case "Next":
currentPage++;
break;
case "Previous":
currentPage--;
break;
default:
currentPage = 1;
break;
}

pageLbl.Text = "Page " + currentPage + " of " + totalPages;

// Clear rows and add new results.
custTable.Rows.Clear();

foreach (DataRow myRow in tmpTable.Rows)
custTable.ImportRow(myRow);

// Preserve first and last primary key values.
DataRow[] ordRows = custTable.Select("", "CustomerID ASC");
firstVisibleCustomer = ordRows[0][0].ToString();
lastVisibleCustomer = ordRows[custTable.Rows.Count - 1][0].ToString();
}
}

public PagingSample()
{
// Initialize controls and add to form.
this.ClientSize = new Size(360, 274);
this.Text = "NorthWind Data";

myGrid.Location = new Point(10,10);
myGrid.Size = new Size(340, 220);
myGrid.AllowSorting = true;
myGrid.CaptionText = "NorthWind Customers";
myGrid.ReadOnly = true;
myGrid.AllowNavigation = false;
myGrid.PreferredColumnWidth = 150;

prevBtn.Text = "<<";
prevBtn.Size = new Size(48, 24);
prevBtn.Location = new Point(92, 240);
prevBtn.Click += new EventHandler(Prev_OnClick);

nextBtn.Text = ">>";
nextBtn.Size = new Size(48, 24);
nextBtn.Location = new Point(160, 240);

pageLbl.Text = "No Records Returned.";
pageLbl.Size = new Size(130, 16);
pageLbl.Location = new Point(218, 244);

this.Controls.Add(myGrid);
this.Controls.Add(prevBtn);
this.Controls.Add(nextBtn);
this.Controls.Add(pageLbl);
nextBtn.Click += new EventHandler(Next_OnClick);

// Populate DataSet with first page of records and bind to grid.
GetData("Default");
DataView custDV = new DataView(custTable, "", "CustomerID", DataViewRowState.CurrentRows);
myGrid.SetDataBinding(custDV, "");
}

public static void Prev_OnClick(object sender, EventArgs args)
{
GetData("Previous");
}

public static void Next_OnClick(object sender, EventArgs args)
{
GetData("Next");
}
}

public class Sample
{
static void Main()
{
Application.Run(new PagingSample());
}
}