Asp.net中DataGrid控件的自定义分页

使用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。<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

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: <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /><chmetcnv w:st="on" unitname="pt" sourcevalue="9" hasspace="False" negative="False" numbertype="1" tcsc="0">9pt</chmetcnv>" 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="<chmetcnv w:st="on" unitname="pt" sourcevalue="9" hasspace="False" negative="False" numbertype="1" tcsc="0">9pt</chmetcnv>" Mode="NumericPages"></PagerStyle>

</asp:datagrid></TD>

</TR>

</TABLE>

</form>

这里使用的数据源还是假设为Northwind的Customers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：

<?xml:namespace prefix = v ns = "urn:schemas-microsoft-com:vml" /><shapetype id="_x0000_t75" coordsize="21600,21600" o:spt="75" o:preferrelative="t" path="m@4@5l@4@11@9@11@9@5xe" filled="f" stroked="f"><stroke joinstyle="miter"></stroke><formulas><f eqn="if lineDrawn pixelLineWidth 0"></f><f eqn="sum @0 1 0"></f><f eqn="sum 0 0 @1"></f><f eqn="prod @2 1 2"></f><f eqn="prod @3 21600 pixelWidth"></f><f eqn="prod @3 21600 pixelHeight"></f><f eqn="sum @0 0 1"></f><f eqn="prod @6 1 2"></f><f eqn="prod @7 21600 pixelWidth"></f><f eqn="sum @8 21600 0"></f><f eqn="prod @7 21600 pixelHeight"></f><f eqn="sum @10 21600 0"></f></formulas><path o:extrusionok="f" gradientshapeok="t" o:connecttype="rect"></path><lock v:ext="edit" aspectratio="t"></lock></shapetype>

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。