DevExpress的GridControl的实时加载数据解决方案（取代分页）

Posted 2020-07-23 冰封的心

http://blog.csdn.net/educast/article/details/4769457

evExpress是一套第三方控件

其中有类似DataGridView的控件

今天把针对DevExpress.XtraGrid.GridControl实时加载数据的功能开发出来了

分享给大家

欢迎讨论

Code
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using DevExpress.XtraGrid;
using DevExpress.XtraGrid.Views.Grid;
namespace Life365.CallCenter
{
public class GridCreator<T> where T: new()
    {
//一页有多少条数据
private int page_size = 30;
public int PageSize
        {
get { return page_size; }
        }
/// <summary>
/// 过滤条件
/// </summary>
public string Filter
        {
get;
set;
        }
/// <summary>
/// 排序条件
/// </summary>
public string OrderBy
        {
get;
set;
        }
/// <summary>
/// 数据访问类
/// </summary>
public BaseProxy Proxy
        {
get;
set;
        }
private int row_count;
/// <summary>
/// 总行数
/// </summary>
public int RowCount
        {
get {return row_count;}
        }
private int page_num = 1;
/// <summary>
/// 当前的数据页
/// </summary>
public int PageNum
        {
get { return page_num; }
        }
//缓存的数据
private List<T> data_list = new List<T>();
private GridCreator()
        { 
        }
/// <summary>
/// 构造函数
/// </summary>
public GridCreator(GridControl grid,BaseProxy proxy)
        {
            ((GridView)grid.MainView).TopRowChanged += new EventHandler(grid_TopRowChanged);
this.Proxy = proxy;
            grid.DataSource = data_list;
        }
/// <summary>
/// 获取前两页数据
/// </summary>
private void GetTwoPageData()
        {
            data_list.InsertRange(0, GetData());
            page_num++;
            data_list.InsertRange(page_size, GetData());
        }        
/// <summary>
/// grid下拉事件
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
void grid_TopRowChanged(object sender, EventArgs e)
        {
            GridView grid = sender as GridView;
if (grid.TopRowIndex >= (page_num - 1) * page_size)
            {
//当看完一页数据的时候开始取数据
                page_num++;
                List<T> test = GetData();
                data_list.InsertRange((page_num - 1)* page_size, test);
            }
        }
/// <summary>
/// 实时的加载数据函数
/// </summary>
/// <returns></returns>
public List<T> GetData()
        {
return Proxy.GetDataList(this.Filter, this.OrderBy, this.page_size,this.page_num, ref this.row_count) as List<T>;
        }
    }
}

T泛型约束是需要加载数据的类型

BaseProxy是访问数据库的基类，其中包含GetDataList的虚方法

继承自BaseProxy的GetDataList为

Code
public override object GetDataList(string filter, string order_by, int page_size, int page_num, ref int count)
        {
            count = 1000;
            List<RegionEntity> regions = new List<RegionEntity>();
for (int i = 0; i < page_size; i++)
            {
                regions.Add(new RegionEntity() { SR_RegionName = ((page_num-1)*page_size+i).ToString() });
            }
return regions;
        }

这里的RegionEntity就是前面提到的某一种类型的T

数据提供程序是模拟出来的（测试驱动开发，哈哈）

你可以在这个函数里写数据库访问方法

具体调用方法如下

Code
GridCreator<RegionEntity> creator = new GridCreator<RegionEntity>(gridShop,new UtilsProxy());

UtilsProxy类继承自BaseProxy并重写了GetDataList方法

gridShop就是当前窗体的DevExpress.XtraGrid.GridControl控件

RegionEntity针对泛型类型

用起来还是蛮方便的