c# - Getting InvalidOperationException when using PerformanceCounters -

getting:

exception thrown: 'system.invalidoperationexception' in system.dll

additional information:

category not exist.

the code :

using system; using system.collections.generic; using system.componentmodel; using system.data; using system.diagnostics; using system.drawing; using system.linq; using system.text; using system.threading.tasks; using system.windows.forms;  namespace windowsformsapplication8 { public partial class form1 : form {     performancecounter cpucounter;     performancecounter ramcounter;     public form1()     {         initializecomponent();     }     int timex = 0;     private void timer1_tick(object sender, eventargs e)     {         cpucounter = new performancecounter();         cpucounter.categoryname = "processor";         cpucounter.countername = "% processor time";         cpucounter.instancename = "_total";           float cpuusage = 0.00f;         cpucounter.nextvalue();         cpuusage = cpucounter.nextvalue();         textbox1.text = cpuusage.tostring();           ramcounter = new performancecounter("memory", "available mbytes");         float ram = ramcounter.nextvalue();         textbox2.text = ram.tostring();          chart1.series["cpu usage"].points.addxy(timex, (int)cpuusage);         chart2.series["memory use"].points.addxy(timex, (int)ram);      }      private void button1_click(object sender, eventargs e)     {        timer1.start();     }      private void button2_click(object sender, eventargs e)     {         timer1.stop();     } } } 

getting errors on every .nextvalue();

i have tried adding processor information in categoryname, doesn't either.

edit: @jim code after making changes :

using system; using system.collections.generic; using system.componentmodel; using system.data; using system.drawing; using system.linq; using system.text; using system.threading.tasks; using system.windows.forms; using system.diagnostics; namespace windowsformsapplication12 { public partial class form1 : form {     performancecounter cpucounter;     performancecounter ramcounter;      public form1()     {         initializecomponent();          initializecounters();     }      private void initializecounters()     {         cpucounter = new performancecounter();         cpucounter.categoryname = "processor";         cpucounter.countername = "% processor time";         cpucounter.instancename = "_total";         // ramcounter = new performancecounter("memory", "available mbytes");     }      int timex = 0;     private void timer1_tick(object sender, eventargs e)     {         float cpuusage = 0.00f;         cpuusage = cpucounter.nextvalue();         textbox1.text = cpuusage.tostring();          float ram = ramcounter.nextvalue();         textbox2.text = ram.tostring();          // chart stuff         //chart1.series["cpu usage"].points.addxy(timex, (int)cpuusage);         //chart2.series["memory use"].points.addxy(timex, (int)ram);     }      private void button1_click(object sender, eventargs e)     {         timer1.start();     }      private void button2_click(object sender, eventargs e)     {         timer1.stop();     } } 

}

you creating new performance counters every time timer ticks, need initialize counters once.

form1 code behind

performancecounter cpucounter;    performancecounter ramcounter;  public form1() {     initializecomponent();      initializecounters(); }  private void initializecounters() {     cpucounter = new performancecounter();     cpucounter.categoryname = "processor";     cpucounter.countername = "% processor time";     cpucounter.instancename = "_total";      ramcounter = new performancecounter("memory", "available mbytes"); }  int timex = 0; private void timer1_tick(object sender, eventargs e) {             float cpuusage = 0.00f;     cpuusage = cpucounter.nextvalue();     textbox1.text = cpuusage.tostring();      float ram = ramcounter.nextvalue();     textbox2.text = ram.tostring();      // chart stuff     //chart1.series["cpu usage"].points.addxy(timex, (int)cpuusage);     //chart2.series["memory use"].points.addxy(timex, (int)ram); }  private void button1_click(object sender, eventargs e) {     timer1.start(); }  private void button2_click(object sender, eventargs e) {     timer1.stop(); } 

side note:

also dispose counters when not using them anymore. maybe on form closing event.

cpucounter.dispose(); ramcounter.dispose(); 

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result

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case of error

if example still throws error, because 1 or more performance counters on system corrupted.

rebuild performance counters:

• open command prompt (with admin privileges)
• run command: lodctr /r

the message:

info: rebuilt performance counter setting ...

will appear on success.

in case receive message:

unable rebuild performance counter setting system backup store, error code 2

possible solutions:

• close running programs
• make sure use lodctr /r uppercase r
• if in directory system32 move directory syswow64 (with cd.. > cd syswow64) , retry lodctr /r command in directory