1、页面上
<asp:GridView runat="server" AutoGenerateColumns="False" AllowPaging="True" Width="100%" AllowSorting="True" OnPageIndexChanging="Case_GV_PageIndexChanging" DataKeyNames="ObjectID" DataSourceID="dataSource" OnDataBound="Case_GV_DataBound" OnSorting="Case_GV_Sorting">
…
</asp:GridView>
<asp:ObjectDataSource ID="dataSource" runat="server"></asp:ObjectDataSource>
2、页面后台代码，在Page_Load(…)时执行BindData()
#region 绑定案件列表 BindData()
/// <summary>
/// 绑定案件列表
/// </summary>
private void BindData()
{
//初始化aspx上的数据源
InitDataSource();
dataSource.SelectParameters["opathStr"].DefaultValue = OPath;
dataSource.SelectParameters["userID"].DefaultValue = CurrentUser.UniqueID;
//从US的个性化设置中获取PageSize
Case_GV.PageSize = int.Parse(CurrentUser.Profile["PageSize"].Value.ToString());
}
/// <summary>
/// 初始化aspx上的数据源
/// </summary>
private void InitDataSource()
{
Parameter opathPara = new Parameter("opathStr", TypeCode.String, OPath);
Parameter userPara = new Parameter("userID", TypeCode.String, CurrentUser.UniqueID);
dataSource.EnablePaging = true;
dataSource.StartRowIndexParameterName = "startIndex";
dataSource.MaximumRowsParameterName = "endIndex";
//获取案件数目的方法
dataSource.SelectCountMethod = "GetViewCaseCount";
//获取案件对象的方法
dataSource.SelectMethod = "GetViewCaseList";
dataSource.SortParameterName = "sortExpression";
dataSource.TypeName = "Com.iFlytek.PoliceOnline2.Business.DataObjectsManger.CaseManager";
if (dataSource.SelectParameters["opathStr"] == null)
{
dataSource.SelectParameters.Add(opathPara);
}
if (dataSource.SelectParameters["userID"] == null)
{
dataSource.SelectParameters.Add(userPara);
}
}
#endregion
3、业务层获取数据的方法 Namespace Com.iFlytek.PoliceOnline2.Business.DataObjectsManger.CaseManager. GetViewCaseList(……):List<Case>
Namespace Com.iFlytek.PoliceOnline2.Business.DataObjectsManger
Class CaseManager
{
public static List<Case> GetViewCaseList(string userID, string opathStr, int startIndex, int endIndex, string sortExpression)
{
if (sortExpression == "")
{
sortExpression = "InsertTime Desc";
}
if ((opathStr == "")||(opathStr == null))
{
opathStr = "1=1";
}
ObjectSet objectSet = new ObjectSet();
objectSet = NodObjectManager.GetNodObjectSet(string.Format("Case[{0} and {1}]", RightManager.GetViewRightString(userID), opathStr), startIndex, endIndex, sortExpression);
List<Case> list = new List<Case>();
foreach (DataObject dataObject in objectSet)
{
list.Add((Case)dataObject);
}
return list;
}
}
4、底层获取数据的管理类
namespace Com.iFlytek.PoliceOnline2.Business
{
/// <summary>
/// NodObject管理类
/// </summary>
internal static class NodObjectManager
{
/// <summary>
/// 获取单个DataObject
/// </summary>
/// <param ></param>
/// <returns></returns>
internal static DataObject GetNodObject(string opathStr)
{
DataObject obj = NodObject.CurrentSession.GetObject(opathStr);
return obj;
}
/// <summary>
/// 获取ObjectSet
/// </summary>
/// <param ></param>
/// <param ></param>
/// <returns></returns>
internal static ObjectSet GetNodObjectSet(string opathStr, string sortExpression)
{
return GetNodObjectSet(opathStr, 0, -1, sortExpression);
}
/// <summary>
/// 获取ObjectSet，实现分页功能
/// </summary>
/// <param >OPath语句</param>
/// <param >开始记录数</param>
/// <param >结束记录数</param>
/// <param >排序表达式：Id、Id DESC</param>
/// <returns></returns>
internal static ObjectSet GetNodObjectSet(string opathStr,int startIndex,int endIndex,string sortExpression)
{
string orderby = string.Empty;
if (!string.IsNullOrEmpty(sortExpression))
{
if (!sortExpression.ToUpper().Contains("DESC"))
{
orderby = string.Format(" Orderby ({0} ASC)", sortExpression);
}
else
{
orderby = string.Format(" Orderby ({0})", sortExpression);
}
}
ObjectReader objReader = NodObject.CurrentSession.GetObjectReader(string.Format("{0} {1}", opathStr, orderby));
while (0 < startIndex)
{
if (!objReader.Read())
{
return new ObjectSet();
}
startIndex--;
}
ObjectSet objectSet = new ObjectSet();
if (endIndex < 0)
endIndex = int.MaxValue;
while (endIndex > 0 && objReader.Read())
{
objectSet.Add(objReader.Current);
endIndex--;
}
objReader.Close();
return objectSet;
}
/// <summary>
/// 获取符合条件的对象数
/// </summary>
/// <param >OPath语句</param>
/// <returns></returns>
internal static int GetNodObjectCount(string opathStr)
{
return NodObject.CurrentSession.GetObjectCount(opathStr);
}
}
}
说明：
A、在页面的代码中，标红的地方要注意，gridview设置了datasourceid，这就设置了gridview的数据源为id等于datasourceid的objectdatasource。
B、具体数据层分页的代码在NodObjectManager. GetNodObjectSet(……): ObjectSet，通过ObjectReader来过滤不需要显示在页面的数据。
C、页面后台代码中InitDataSource()方法里面， dataSource.TypeName = "Com.iFlytek.PoliceOnline2.Business.DataObjectsManger.CaseManager";和dataSource.SelectMethod = "GetViewCaseList";就指明了datasource获取数据时需要调用的类名和方法名，如果方法有重载那么怎么找到具体是那个方法呢？
Parameter opathPara = new Parameter("opathStr", TypeCode.String, OPath);
Parameter userPara = new Parameter("userID", TypeCode.String, CurrentUser.UniqueID);
dataSource.StartRowIndexParameterName = "startIndex";
dataSource.MaximumRowsParameterName = "endIndex";
dataSource.SortParameterName = "sortExpression";
if (dataSource.SelectParameters["opathStr"] == null)
{
dataSource.SelectParameters.Add(opathPara);
}
if (dataSource.SelectParameters["userID"] == null)
{
dataSource.SelectParameters.Add(userPara);
}
这部分代码就指明了这个方法所需要的参数，这个方法指明了有5个参数（opathStr,userID,startIndex,endIndex,sortExpression），asp.net回通过反射来寻找在Com.iFlytek.PoliceOnline2.Business.DataObjectsManger.CaseManager类中，有和以上五个参数同名的参数的方法GetViewCaseList，并自动调用他获取数据。
D、在InitDataSource()中dataSource.SelectCountMethod = "GetViewCaseCount";为数据源指明了获取整个数据条数的方法。