分页控件很多人都写过，但不像DataPager那样要传入个PagedCollectionView才行，一般传入总记录数和分页大小就可以了，所以，我们给Datapager增加一个扩展方法来绑定总记录数和分页大小:
public static class DataPageExtension
{
public static void BindSource(this DataPager dataPager, int totalCount, int pageSize)
{
List list = new List(totalCount);
for (int i = 0; i < totalCount; i++) list.Add(i);
PagedCollectionView pcv = new PagedCollectionView(list);
pcv.PageSize = pageSize;
dataPager.Source = pcv;
}
}
WCF服务端的分页方法如下：
[OperationContract]
public List GetEmployeeList(EmployeeFilter filter,out int totalCount)
{
using (TestDBEntities db = new TestDBEntities())
{
int rowsCount = 0;
StringBuilder sbSql = new StringBuilder("True ");
if (filter.DeptID != new Guid())
sbSql.Append(string.Format("and it.Departments.DepartmentID = Guid'{0}'", filter.DeptID));
sbSql.Append(string.Format("and it.EmpolyeeName like '%{0}%'", filter.EmpName));
var query = from emp in db.Employees.Where(sbSql.ToString())
select new MyEmployee
{
ID = emp.EmployeeID,
Name = emp.EmpolyeeName,
Sex = emp.EmployeeSex ? "男" : "女",
Age = emp.EmployeeAge,
Address = emp.EmployeeAddress,
DeptName = emp.Departments.DepartmentName
};
if (filter.PageIndex <= 0)
rowsCount = query.Count();
totalCount = rowsCount;
query = query.OrderBy(t => t.Name).Skip(filter.PageIndex * filter.PageSize).Take(filter.PageSize);
return query.ToList();
}
}
上面的代码实现了使用Entity SQl的动态查找功能和分页功能，可以看到：只有当pageindex 等于0的时候才计算总记录数，提高了方法执行的效率；方法的输入参数和输出参数都进行了实体类的封装，建议在实际项目中也这样做，特别是在使用依赖注入的时候。
在客户端（Silverlight项目）中引用好服务后，页面的cs代码如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.Windows.Data;
using DataPagerTest.EmployeeServiceReference;
namespace DataPagerTest
{
public partial class MainPage : UserControl
{
EmployeeServiceClient client = new EmployeeServiceClient();
EmployeeFilter filter = new EmployeeFilter();
public MainPage()
{
InitializeComponent();
}
private void UserControl_Loaded(object sender, RoutedEventArgs e)
{
dpEmployee.PageIndexChanged += new EventHandler(dpEmployee_PageIndexChanged);
cbDept.SelectionChanged += new SelectionChangedEventHandler(cbDept_SelectionChanged);
BindCombox();
}
void cbDept_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
BindGrid(0);
}
void dpEmployee_PageIndexChanged(object sender, EventArgs e)
{
BindGrid(dpEmployee.PageIndex);
}
private void btnQuery_Click(object sender, RoutedEventArgs e)
{
BindGrid(0);
}
private void BindGrid(int pageIndex)
{
Departments dept = cbDept.SelectedItem as Departments;
filter.DeptID = dept.DepartmentID;
filter.EmpName = tbEmpName.Text.Trim();
filter.PageIndex = pageIndex;
filter.PageSize = 9;
client.GetEmployeeListCompleted += new EventHandler(client_GetEmployeeListCompleted);
client.GetEmployeeListAsync(filter);
}
void client_GetEmployeeListCompleted(object sender, GetEmployeeListCompletedEventArgs e)
{
dgEmployee.ItemsSource = e.Result;
if (filter.PageIndex <= 0)
dpEmployee.BindSource(e.totalCount, filter.PageSize);
}
void BindCombox()
{
client.GetDepartmentListCompleted += new EventHandler(client_GetDepartmentListCompleted);
client.GetDepartmentListAsync();
}
void client_GetDepartmentListCompleted(object sender, GetDepartmentListCompletedEventArgs e)
{
cbDept.ItemsSource = e.Result;
cbDept.DisplayMemberPath = "DepartmentName";
cbDept.SelectedIndex = 0;
BindGrid(0);
}
}
}
在PageIndex等于0的时候调用BindSource扩展方法来绑定总记录数和页大小；里面还有个关于Combobox的数据绑定方法。这样的分页方法不知大家有何评价，欢迎拍砖。
/本篇文章来源于Java秀，原文出处：http://www.java.sh/article/sliverlight/1237_2.html
