Hi here is my C# code getting idexoutofrange exception may I know how to fix it

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C#

private void ShowOldMedicalNoteCommandHandler()
      {
          if (null != this.MedicalElements)
          {
              NavigatedIndex = NavigatedIndex + 1;
              var medicalNote = MedicalElements[NavigatedIndex];
              NavigateMedicalNote(medicalNote);
              IsNewestEnabled = true;
              IsOldestEnabled = MedicalElements.Count - 1 != NavigatedIndex;
          }
      }

What I have tried:

C#

private void ShowOldMedicalNoteCommandHandler()
      {
          if (null != this.MedicalElements)
          {
              NavigatedIndex = NavigatedIndex + 1;
              var medicalNote = MedicalElements[NavigatedIndex];
              NavigateMedicalNote(medicalNote);
              IsNewestEnabled = true;
              IsOldestEnabled = MedicalElements.Count - 1 != NavigatedIndex;
          }
      }

Posted 20-Dec-16 18:59pm

Member 12915158

Updated 20-Dec-16 19:09pm

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Mehdi Gholam · Answer 1 · 2016-12-20T19:08:00

Obviously NavigatedIndex is greater than the MedicalElements.Count so just check for it:

C#

...
NavigatedIndex = NavigatedIndex + 1;
if(NavigatedIndex < MedicalElements.Count)
{
   var medicalNote = MedicalElements[NavigatedIndex];
   NavigateMedicalNote(medicalNote);
   IsNewestEnabled = true;
   IsOldestEnabled = MedicalElements.Count - 1 != NavigatedIndex;
}
else
{
 // handle this case accordingly 
}

Peter Leow · Answer 2 · 2016-12-20T19:09:00

Solution 2

Apparently, the mistake stems from:

MedicalElements[NavigatedIndex]

when the value of

NavigatedIndex

is greater than the number of items in

MedicalElements

minus one, not to forget indices in a collection like array start from zero. To prevent this, use Count [^].

Posted 20-Dec-16 19:09pm

Peter Leow

Updated 20-Dec-16 19:15pm

v5