日期:2014-05-20  浏览次数:21362 次

怎样在mschart的x轴上设置滚动条
用mschart做了一个柱形图,但当数据过多时,柱形图会越来越细。如何在x轴上设置滚动条,这样柱形图就不会因为数据的增多而变形。我在chart属性里找到了chartarea--axis--dataview--scrollbar,但设置后没用。有没有前辈做过类似的东西,请不吝赐教!谢谢!!

------解决方案--------------------
设置可视区域 的起始、结束位置
------解决方案--------------------
MSChart demo里面有事例,例如:

VB.NET code
Imports System.Windows.Forms.DataVisualization.Charting
...
Private SelectionStart As Double = Double.NaN
...

Protected Overrides Function ProcessDialogKey(keyData As Keys) As Boolean
   ' Avoid dialog processing of arrow keys
   If keyData = Keys.Left Or keyData = Keys.Right Then
      Return False
   End If
   Return MyBase.ProcessDialogKey(keyData)
End Function 'ProcessDialogKey

Private Sub Chart1_Click(sender As Object, e As System.EventArgs) Handles Chart1.Click
   ' Set input focus to the chart control
   chart1.Focus()
   
   ' Set the selection start variable to that of the current position
   Me.SelectionStart = chart1.ChartAreas("Default").CursorX.Position
End Sub 'chart1_Click

Private Sub ProcessSelect(e As System.Windows.Forms.KeyEventArgs)
   ' Process keyboard keys
   If e.KeyCode = Keys.Right Then
      ' Make sure the selection start value is assigned
      If Me.SelectionStart = Double.NaN Then
         Me.SelectionStart = chart1.ChartAreas("Default").CursorX.Position
      End If 
      ' Set the new cursor position 
      chart1.ChartAreas("Default").CursorX.Position += chart1.ChartAreas("Default").CursorX.Interval
   Else
      If e.KeyCode = Keys.Left Then
         ' Make sure the selection start value is assigned
         If Me.SelectionStart = Double.NaN Then
            Me.SelectionStart = chart1.ChartAreas("Default").CursorX.Position
         End If 
         ' Set the new cursor position 
         chart1.ChartAreas("Default").CursorX.Position -= chart1.ChartAreas("Default").CursorX.Interval
      End If
   End If 
   ' If the cursor is outside the view, set the view
   ' so that the cursor can be seen
   SetView()
   
   
   chart1.ChartAreas("Default").CursorX.SelectionStart = Me.SelectionStart
   chart1.ChartAreas("Default").CursorX.SelectionEnd = chart1.ChartAreas("Default").CursorX.Position
End Sub 'ProcessSelect


Private Sub SetView()
   ' Keep the cursor from leaving the max and min axis points
   If chart1.ChartAreas("Default").CursorX.Position < 0 Then
      chart1.ChartAreas("Default").CursorX.Position = 0
   
   Else
      If chart1.ChartAreas("Default").CursorX.Position > 75 Then
         chart1.ChartAreas("Default").CursorX.Position = 75
      End If 
   End If 
   ' Move the view to keep the cursor visible
   If chart1.ChartAreas("Default").CursorX.Position < chart1.ChartAreas("Default").AxisX.ScaleView.Position Then
      chart1.ChartAreas("Default").AxisX.ScaleView.Position = chart1.ChartAreas("Default").CursorX.Position
   
   Else
      If chart1.ChartAreas("Default").CursorX.Position > chart1.ChartAreas("Default").AxisX.ScaleView.Position + chart1.ChartAreas("Default").AxisX.ScaleView.Size Then
         chart1.ChartAreas("Default").AxisX.ScaleView.Position = chart1.ChartAreas("Default").CursorX.Position - chart1.ChartAreas("Default").AxisX.ScaleView.Size
      End If
   End If
End Sub 'SetView


Private Sub ProcessScroll(e As System.Windows.Forms.KeyEventArgs)
   ' Process keyboard keys
   If e.KeyCode = Keys.Right Then
      ' Set the new cursor position 
      chart1.ChartAreas("Default").CursorX.Position += chart1.ChartAreas("Default").CursorX.Interval
   
   Else
      If e.KeyCode = Keys.Left Then
         ' Set the new cursor position 
         chart1.ChartAreas("Default").CursorX.Position -= chart1.ChartAreas("Default").CursorX.Interval
      End If 
   End If
   
   ' If the cursor is outside the view, set the view
   ' so that the cursor can be seen
   SetView()
   
   ' Set the selection start variable in case shift arrows are selected
   Me.SelectionStart = chart1.ChartAreas("Default").CursorX.Position
   
   ' Reset the old selection start and end
   chart1.ChartAreas("Default").CursorX.SelectionStart = Double.NaN
   chart1.ChartAreas("Default").CursorX.SelectionEnd = Double.NaN
End Sub 'ProcessScroll


Private Sub Chart1_KeyUp(sender As Object, e As System.Windows.Forms.KeyEventArgs) Handles Chart1.KeyUp
   
   If e.KeyCode = Keys.Right Or e.KeyCode = Keys.Left Then
      ' If the key event is shifted, process as a selection
      If e.Shift Then
         ProcessSelect(e)
      ' Process as a scroll
      Else
         ProcessScroll(e)
      End If
   
   ' on enter, zoom the selection
   Else
      If e.KeyCode = Keys.Enter Then
         Dim start, [end] As Double
         
         If chart1.ChartAreas("Default").CursorX.SelectionStart > chart1.ChartAreas("Default").CursorX.SelectionEnd Then
            start = chart1.ChartAreas("Default").CursorX.SelectionEnd
            [end] = chart1.ChartAreas("Default").CursorX.SelectionStart
         Else
            [end] = chart1.ChartAreas("Default").CursorX.SelectionEnd
            start = chart1.ChartAreas("Default").CursorX.SelectionStart
         End If
         
         ' Return if no selection actually made
         If start = [end] Then
            Return
         End If 
         ' Zoom the selection
         chart1.ChartAreas("Default").AxisX.ScaleView.Zoom(start, [end] - start, DateTimeIntervalType.Number, True)
         
         ' Reset selection values
         Me.SelectionStart = chart1.ChartAreas("Default").CursorX.Position
         chart1.ChartAreas("Default").CursorX.SelectionStart = Double.NaN
         chart1.ChartAreas("Default").CursorX.SelectionEnd = Double.NaN
      
      
      Else
         If e.KeyCode = Keys.Back Then
            ' Reset zoom back to previous view state
            chart1.ChartAreas("Default").AxisX.ScaleView.ZoomReset(1)
            
            ' Reset selection values
            Me.SelectionStart = chart1.ChartAreas("Default").CursorX.Position
            chart1.ChartAreas("Default").CursorX.SelectionStart = Double.NaN
            chart1.ChartAreas("Default").CursorX.SelectionEnd = Double.NaN
         End If
      End If 
   End If
End Sub 'chart1_KeyUp