Multi Line Chart Control

 

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This control class CLineChartCtrl is derived from CWnd. The original idea and part of
the code are from Ken C. Len’s CHistogramCtrl. I did
some changes to make the control work in multi lines. I was trying to make a CPU usage app
that would work both under Windows95/98 and NT, but I failed. I know now how to get CPU
usage under Windows 95/98 through the registry (See the article Q174631 from Microsoft).
But the code does not work under NT:-).

I found something very interesting in Ndis.vxd(Win95/98) and Ndis.Dll(NT) – there is a
function called NdisGetCurrentProcessorCpuUsage(). Will this function solve all
the problems? I don’t know. I can load the library and receive the address for the
function, but I don’t have the parameters. If anyone knows anything about it, I will
appreciate if you let me know!

The sample project is created and compiled with Visual C++ 5.0 SP3 under Windows 98.

How to use

1. Use the MS Visual C++ dialog editor to place a custom control on the dialog, and
enter "LINE_CHART_CTRL" as the Class name.

2. Add a CPieChartCtrl class member in the header file

#include "LineChartCtrl.h"
...
CLineChartCtrl m_wndLineChart;

3. Subclass the class member with the control in InitDialog()

//IDC_LINE_CHART_CTRL is the control ID
m_wndLineChart.SubclassDlgItem(IDC_LINE_CHART_CTRL, this);

4. Initiate the control

m_wndLineChart.Add(RGB(0,255,0),100, 0);
m_wndLineChart.Add(RGB(255,255,0),100, 0);
m_wndLineChart.Add(RGB(0,255,255),100, 0);

SetTimer(1, 500, NULL); // Create a timer to update the control

5. Add update code in OnTimer(UINT nIDEvent)

m_wndLineChart.SetPos(0,nPos0); // nPos0 is the currect postion
m_wndLineChart.SetPos(1,nPos1); // nPos1 is the currect postion
m_wndLineChart.SetPos(2,nPos2); // nPos2 is the currect postion
m_wndLineChart.Go(); // Make sure that the control updates with the new value

Last updated: 13 August 1998

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