Asp.net中DataGrid控件的自定义分页

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Asp.netDataGrid控件的自定义分页

2004-10-28

         使用DataGrid时自带的分页实现起来虽然比较方便,但是效率不高,每次都需要读取所有页(整个记录集),而加载的只是其中一页,造成了资源的浪费,记录多又会使效率变得很低。下面通过DataGrid的自定义分页功能来减少资源使用和提高效率。

         实现的关键是设置AllowCustomPaging属性位True,并把VirtualItemCount属性设置位总的记录数,给分页提供依据,前台的主要代码如下:

<form id="Form1" method="post" runat="server">

                            <TABLE id="Table1" style="FONT-SIZE: 9pt" cellSpacing="1" cellPadding="1" width="450" align="center"

                                     border="1">

                                     <TR>

                                               <TD>

                                                        <asp:datagrid id="DataGrid1" runat="server" Width="100%" AllowPaging="True" AllowCustomPaging="True">

                                                                 <PagerStyle Font-Size="9pt" Mode="NumericPages"></PagerStyle>

                                                        </asp:datagrid></TD>

                                     </TR>

                            </TABLE>

                   </form>

这里使用的数据源还是假设为NorthwindCustomers表。

下面是访问单页的存储过程,实现方式很多,不过这个是最普通的,

CREATE PROCEDURE [GetCustomersDataPage]

         @PageIndex INT,

         @PageSize  INT,

         @RecordCount INT OUT,

         @PageCount INT OUT

AS

SELECT @RecordCount = COUNT(*)  FROM   Customers

SET @PageCount = CEILING(@RecordCount * 1.0 / @PageSize)

DECLARE @SQLSTR NVARCHAR(1000)

IF @PageIndex = 0 OR @PageCount <= 1

         SET @SQLSTR =N'SELECT TOP '+STR( @PageSize )+

'  CustomerID, CompanyName,Address,Phone  FROM   Customers ORDER BY CustomerID DESC'

ELSE IF     @PageIndex = @PageCount - 1            

         SET @SQLSTR =N' SELECT * FROM ( SELECT TOP '+STR( @RecordCount - @PageSize * @PageIndex )+

'  CustomerID, CompanyName,Address,Phone  FROM   Customers ORDER BY CustomerID ASC ) TempTable  ORDER BY CustomerID DESC'

ELSE         

        SET @SQLSTR =N' SELECT TOP  '+STR( @PageSize )+' * FROM ( SELECT TOP '+STR( @RecordCount - @PageSize * @PageIndex )+

'  CustomerID, CompanyName,Address,Phone  FROM   Customers ORDER BY CustomerID ASC ) TempTable ORDER BY CustomerID DESC'

EXEC (@SQLSTR)

 

GO

获取记录数和页数都采用存储过程的输出参数。

获取数据源,这里返回一个DataSet

先定义了连个数据成员,

private int pageCount;//页数

private int recordCount;//记录数

//获取单页数据

private static DataSet GetCustomersData(int pageIndex,int pageSize,ref int recordCount,ref int pageCount)

{

     string connString = ConfigurationSettings.AppSettings["ConnString"];

     SqlConnection conn = new SqlConnection(connString);

     SqlCommand comm = new SqlCommand("GetCustomersDataPage",conn);

 

     comm.Parameters.Add(new SqlParameter("@PageIndex",SqlDbType.Int));

     comm.Parameters[0].Value = pageIndex;

 

     comm.Parameters.Add(new SqlParameter("@PageSize",SqlDbType.Int));

     comm.Parameters[1].Value = pageSize;

 

     comm.Parameters.Add(new SqlParameter("@RecordCount",SqlDbType.Int));

     comm.Parameters[2].Direction = ParameterDirection.Output;

 

     comm.Parameters.Add(new SqlParameter("@PageCount",SqlDbType.Int));

     comm.Parameters[3].Direction = ParameterDirection.Output;

 

     comm.CommandType = CommandType.StoredProcedure;

     SqlDataAdapter dataAdapter = new SqlDataAdapter(comm);

     DataSet ds = new DataSet();

     dataAdapter.Fill(ds);

 

     recordCount = (int)comm.Parameters[2].Value;

     pageCount = (int)comm.Parameters[3].Value;

 

     return ds;

}

//绑定数据到DataGrid,同时刷新数据总记录数

private void DataGridDataBind()

{

     DataSet ds = GetCustomersData(PageIndex,PageSize,ref recordCount,ref pageCount);

     this.DataGrid1.VirtualItemCount = RecordCount;

     this.DataGrid1.DataSource = ds;

     this.DataGrid1.DataBind();

}

下面是分页的几个变量属性

public int PageCount

{

     get{return this.DataGrid1.PageCount;}

}

 

public int PageSize

{

     get{return this.DataGrid1.PageSize;}

}

 

public int PageIndex

{

     get{return this.DataGrid1.CurrentPageIndex;}

     set{this.DataGrid1.CurrentPageIndex = value;}

}

 

public int RecordCount

{

     get{return recordCount;}

}

注册DataGrid分页事件

//分页事件处理

private void DataGrid1_PageIndexChanged(object source, System.Web.UI.WebControls.DataGridPageChangedEventArgs e)

{

     DataGrid dg = (DataGrid)source;

     dg.CurrentPageIndex = e.NewPageIndex;

     DataGridDataBind();

}

最好判断当前页面是否是第一次加载,防止重复加载两次数据,

private void Page_Load(object sender, System.EventArgs e)

{

     if(!Page.IsPostBack)

     {

         DataGridDataBind();

     }

}

显示界面如下:


这个例子中没有显示分页的一些参数,我们可以进一步对其进行改进。

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