滾輪翻頁與傳動的翻頁更為方便，經過本人一番探討與琢磨終于在xtragrid的gridview中實現了鼠標滾輪翻頁。
我新建了一個組件繼承原本的GridControl，在組件中添加了一個ImageList,專門存放一些資源圖片。用于實現動態圖的效果。
添加一個自定義委托的參數與枚舉，委托參數用于傳遞分頁的信息。
public class PagingEventArgs : EventArgs { public int PageSize { get; set; } public int PageIndex { get; set; } } public enum LoadState { /// <summary> /// 就緒 /// </summary> Ready, /// <summary> /// 正在讀取 /// </summary> Loading, /// <summary> /// 讀取完成 /// </summary> Finish }
在組件的類里面添加以下字段
/// <summary> /// 頁面大小 /// </summary> private int _int_page_size=20; /// <summary> /// 當前頁索引 /// </summary> private int _int_page_index=1; /// <summary> /// 總記錄數 /// </summary> private int _int_record_count; /// <summary> /// 讀取狀態 /// </summary> private LoadState _LodaState_state;
添加以下屬性
(!IsPaging) (!IsPaging) = (value>,
else
{
while?(this.MainView.DataRowCount > 0)
GridView_main_view.DeleteRow(0);
this.RefreshDataSource();
}
} } /// <summary> /// 每次讀取的行數 /// </summary> public int PageSize { get { if (!IsPaging) return 0; return _int_page_size; } set { if (!IsPaging) return ; _int_page_size = value; } } /// <summary> /// 總頁數 /// </summary> private int PageCount { get { if (RecordCount % PageSize == 0) return RecordCount / PageSize; return RecordCount / PageSize + 1; } } /// <summary> /// Grid /// </summary> private GridView _GridView_main_view { get { return (GridView)this.MainView; } } /// <summary> /// 是否啟用分頁 /// </summary> public bool IsPaging { get; set; }
添加以下委托與事件
/// <summary> /// 內部使用的委托 /// </summary> private Delegate void myDelegate(); /// <summary> /// 滾動翻頁的委托 /// </summary> /// <param name="sender"></param> /// <param name="e"></param> public delegate void ScrollingToPageEventHandler(object sender, PagingEventArgs e); /// <summary> /// 滾動翻頁的事件 /// </summary> public event ScrollingToPageEventHandler OnScrollingToPage;
以下則是一些對控件的設置，按照各人喜好可以有所更改。
/// <summary> /// 設置分頁欄 /// </summary> private void InitEmbeddedNavigator() {this.EmbeddedNavigator.CustomButtons.AddRange(new DevExpress.XtraEditors.NavigatorCustomButton[] { new DevExpress.XtraEditors.NavigatorCustomButton(-1, -1, true, false, "", null)}); this.EmbeddedNavigator.TextStringFormat = " 當前 {1} 行數據 "; this.UseEmbeddedNavigator = true; } /// <summary> /// 設置gridView /// </summary> private void InitGridView() { _GridView_main_view.TopRowChanged += new EventHandler(gridView_TopRowChanged); }
為控件的事件注冊以下方法
private void gridControl_Load(object sender, EventArgs e) { if (IsPaging) { _LodaState_state = LoadState.Ready; InitEmbeddedNavigator(); InitGridView(); } } private void gridView_TopRowChanged(object sender, EventArgs e) { lock (this) { if ( _int_page_index > PageCount || _LodaState_state != LoadState.Ready) return; } //檢查是否到達底部 if (_GridView_main_view.IsRowVisible(_GridView_main_view.RowCount - 1) == RowVisibleState.Visible|| _int_page_index==1) { lock (this)//設置成開始讀取狀態 { _LodaState_state = LoadState.Loading; } Thread thread_load_data = new Thread(new ThreadStart(LoadData)); Thread thread_change_text = new Thread(new ThreadStart(ChangeLoadingImage)); thread_change_text.Start(); thread_load_data.Start(); } }
TopRowChanged事件在grid的首行改變了就會觸發，類似于滾動條的Scroll事件。這里開了兩個線程，第一個線程用于讀取數據，第二個線程用于實現動態圖。兩個線程調用的方法都在下面
top_row_index = focus_index = (== (OnScrollingToPage == Exception(= = = (.Parent.Invoke( myDelegate(== (= LoadState.Finish; p_w_picpath_index = (.Parent.InvokeRequired).Parent.Invoke( myDelegate(.EmbeddedNavigator.Buttons.CustomButtons[].Visible = () ( (_LodaState_state != LoadState.Loading) (p_w_picpath_index == = ++ ( .Parent.Invoke( myDelegate(.EmbeddedNavigator.Buttons.CustomButtons[].ImageIndex = (.Parent.InvokeRequired).Parent.Invoke( myDelegate(.EmbeddedNavigator.Buttons.CustomButtons[].Visible = (= ++
不過這個代碼有點問題，當GridControl綁定的數據源有相同實例的子項時，隨著RefreshData方法的調用會不停觸發TopRowChanged事件，確切的原因還沒搞清楚，解決這個問題就是要不去除數據源上相同的實例子項，要不就不調用RefreshData方法。
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