Windows 窗体组件 > 公共概念 > 示例 > 如何： 为 XtraGrid 控件中的行指示器添加工具提示

下面的示例展示了如何为 XtraGrid 控件中的行指示器单元格实现实现自定义工具提示。 缺省时，这个网格控件不支持行指示器单元格的工具提示。 要提供工具提示， 则把 ToolTipController 组件拖放到窗体中，把它指派到这个网格控件的 EditorContainer.ToolTipController 属性中，并接管 ToolTipController.GetActiveObjectInfo 事件。

在我们的示例中，这个工具提示将显示 "Row N" 文本，其中 N 是行的序号。

C#CopyCode image复制代码
using DevExpress.Utils;
using DevExpress.XtraGrid.Views.Grid;
using DevExpress.XtraGrid.Views.Grid.ViewInfo;
//...
private void toolTipController1_GetActiveObjectInfo(object sender, 
ToolTipControllerGetActiveObjectInfoEventArgs e) {
    if(e.SelectedControl != gridControl1) return;
    
    ToolTipControlInfo info = null;
    //Get the view at the current mouse position
    GridView view = gridControl1.GetViewAt(e.ControlMousePosition) as GridView;
    if(view == null) return;
    //Get the view's element information that resides at the current position
    GridHitInfo hi = view.CalcHitInfo(e.ControlMousePosition);
    //Display a hint for row indicator cells
    if(hi.HitTest == GridHitTest.RowIndicator) {
        //An object that uniquely identifies a row indicator cell
        object o = hi.HitTest.ToString() + hi.RowHandle.ToString();
        string text = "Row "+ hi.RowHandle.ToString();
        info = new ToolTipControlInfo(o, text);         
    }
    //Supply tooltip information if applicable, otherwise preserve default tooltip (if any)
    if (info != null)
        e.Info = info;
}
Visual BasicCopyCode image复制代码
Imports DevExpress.XtraGrid.Views.Grid
Imports DevExpress.XtraGrid.Views.Grid.ViewInfo

Private Sub ToolTipController1_GetActiveObjectInfo(ByVal sender As Object, _ 
ByVal e As DevExpress.Utils.ToolTipControllerGetActiveObjectInfoEventArgs) _
Handles ToolTipController1.GetActiveObjectInfo
    If Not e.SelectedControl Is gridControl1 Then Return

    Dim info As ToolTipControlInfo = Nothing
    'Get the view at the current mouse position
    Dim view As GridView = gridControl1.GetViewAt(e.ControlMousePosition)
    If view Is Nothing Then Return
    'Get the view's element information that resides at the current position
    Dim hi As GridHitInfo = view.CalcHitInfo(e.ControlMousePosition)
    'Display a hint for row indicator cells
    If hi.HitTest = GridHitTest.RowIndicator Then
        'An object that uniquely identifies a row indicator cell
        Dim o As Object = hi.HitTest.ToString() + hi.RowHandle.ToString()
        Dim text As String = "Row " + hi.RowHandle.ToString()
        info = New ToolTipControlInfo(o, text)
    End If
    'Supply tooltip information if applicable, otherwise preserve default tooltip (if any)
    If Not info Is Nothing Then e.Info = info
End Sub