ListView Sorting on Clicked Column

[SThornton]

Hi,

I have implemented the code from the following url:
Link to Sorting Code at Microsoft
to sort listview columns dynamically.

The pertinant piece of code is:
' Determine whther the type being comapared is a date type
Try
' Parse the two objects into Datetime.
Dim firstdate As System.DateTime = DateTime.Parse(CType(x, ListViewItem).SubItems(col).Text)
Dim seconddate As System.DateTime = DateTime.Parse(CType(y, ListViewItem).SubItems(col).Text)

' Compare the two dates
returnval = DateTime.Compare(firstdate, seconddate)
' If neither compared objects has a valid date format, compare it as a string
Catch
' String Compare the two objects
returnval = [String].Compare(CType(x, ListViewItem).SubItems(col).Text, CType(y, ListViewItem).SubItems(col).Text)
End Try

Trouble is, the data is some of my columns is null and causes the error:

An unhandled exception of type 'System.ArgumentOutOfRangeException' occurred in system.windows.forms.dll

Additional information: Specified argument was out of the range of valid values.

Does anyone know how to make it work when there are nulls in the columns?

[SThornton]

Hi,

I now believe the problem does not lie with nulls in the columns.

I modified the example and nulls work ok.

The problem I believe is due to the indexes of the items/columns not working/being set up correctly.

I add items from the database in the following way:
connPiMSDatabase.Open()
reader = commSelectLocks.ExecuteReader

Dim i As Integer = 0

While reader.Read()

Me.listTransactions.Items.Add(reader.GetValue(0))
Me.listTransactions.Items(i).SubItems.Add(reader.GetValue(1))
Me.listTransactions.Items(i).SubItems.Add(reader.GetValue(2))
Me.listTransactions.Items(i).SubItems.Add(reader.GetDateTime(3))
Me.listTransactions.Items(i).SubItems.Add(reader.GetValue(4))

i = i + 1
End While

When I sort by the following column, it works ok, but when I click on any column I recieve the afore mentioned error.

Any ideas?

[SThornton]

any thoughts?

[Edneeis]

Whats the stacktrace when you get the error? What lines does it give the error on?

[SThornton]

Hi,

Im running it in debug mode, there is no stacktrace, only the error that I have list previously. The messagebox has Break, Continue, Ignore (grayed out) and Help buttons.

Of course the Help button does not provide anything useful.

[Edneeis]

Put the code in a Try..catch block and then catch the exception and show the stacktrace. Maybe that will tell use which line is causing the trouble.

Try
   'code here
Catch ex as Exception
   Msgbox(ex.StackTrace, ,ex.Message)
End Try

[SThornton]

Please see attached message box screen shot

[Edneeis]

Whats the code for line 319 of frmUnlockTool? You can turn line numbering on in the settings: Tools->Options->Text Editor->Basic->Line Numbers

[SThornton]

the line is

returnval = [String].Compare(CType(x, ListViewItem).SubItems(col).Text, CType(y, ListViewItem).SubItems(col).Text)

[Edneeis]

You should put a breakpoint there and then use Quick Watches to see which of those doesn't ahve any items or at least doesn't have the index you are looking for.

[SThornton]

I have placed the line:

MessageBox.Show(CType(x, ListViewItem).SubItems(col).Text)

into the code.

The error:" 1 is not valid value for 'index'", could indicate that the Subitems(1) does not exist?

But the listbox has 5 columns.!!

I am not sure how to proceed.

[SThornton]

Hi,

The error is caused not by the fact that there is no data in the subitem, it is caused by the fact that there is NO subitem at all.

Do you know where I can find code for creating the listview with 5 columns of data?

[Edneeis]

Dim itm As New ListViewItem("1st Col or Item Text")
        itm.SubItems.Add("2nd Col or 1st SubItem")
        itm.SubItems.Add("3rd Col")
        itm.SubItems.Add("4th Col")
        itm.SubItems.Add("5th Col")
        ListView1.Items.Add(itm)

[SThornton]

question solved