Re: list view question

Tech-Archive recommends: Repair Windows Errors & Optimize Windows Performance

From: Dino Buljubasic (dino_at_noplacelikehome.com)
Date: 03/16/04 

Date: Tue, 16 Mar 2004 16:56:04 GMT

Hi Ahmed,

just forgot to tell you, from the class code I sent to you, remove the
line :

 If TypeOf CallerForm Is Demeter25.frmViewEditInactiveDocuments Then

and its end statement (which I think removed already).

Dino

On Tue, 16 Mar 2004 15:30:27 +0200, "Sameh Ahmed"
<essoplus@hotmail.com> wrote:

>Thanks a lot
>will test and update you
>thanks for your time
>Sameh
>"Dino Buljubasic" <dino@noplacelikehome.com> wrote in message
>news:04gc50t2j5ok4vq2uoosuf41h190g04i40@4ax.com...
>>
>> Hi Ahmed,
>>
>> sorting columns in .net is not as simple as in VB. .net sorts column
>> as strings (by default only first colum) so you must provide a way to
>> sort data other than strings and columns other than first column.
>>
>> To do that, you need a new class that implements Icomparer that
>> exposes compare method to compare two objects.
>>
>> Inside the Compare function of your class, you need to check which
>> column to perform sorting on and then to do the sorting on that column
>> by the type of values it contains.
>>
>> To do this you need to:
>> 1) Inside the form that holds the list view - add inside construcotr
>> of the form line:
>> AddHandler lvwMyList.ColumnClick, AddressOf Me.lvwMyList_ColumnClick
>>
>> , then add event lvwMyList_ColumnClick()
>>
>> Now you can build your class clsSorter as :
>>
>> --------- CLASS CODE -------------------------------------------------
>> ' class : classSortER
>> ' purpose : This class is providing functionality to sort list view
>> items in
>> ' A form depending on which column of the list view has
>> been
>> ' clicked. This is necessary because vb.net will
>> otherwise do
>> ' sorting on first column only and the default sort is on
>> strings.
>> ' sorting : ascending by default
>> '
>> ' requirements
>> ' - in form's constructor, add following line of code
>> ' AddHandler lvwMyList.ColumnClick, AddressOf
>> Me.lvwMyList_ColumnClick
>> ' to connect the event handler with the list view
>> column click
>> ' event.
>> ' - add lvwMyList_ColumnClick event in your form
>>
>> Public Class classSorter
>> Implements IComparer ' exposes method (compare) to compare two
>> objects
>>
>> Private col As Integer ' column to sort
>> Private order As SortOrder ' asc or desc
>>
>> 'Dim blnSortingIn As Boolean ' true, sort ascending; false, sort
>> descending
>>
>> Public Sub New()
>> col = 0 ' sort first col by default in ascending order
>> order = SortOrder.Ascending
>> End Sub
>>
>> ' c-tor that receives column to sort and in which order
>> Public Sub New(ByVal aColumn As Integer, ByVal order As SortOrder,
>> ByVal aForm As Form)
>> col = aColumn
>> Me.order = order
>> End Sub
>>
>> ' method to compare two objects (list view items)
>> Public Function Compare(ByVal x As Object, ByVal y As Object) _
>> As Integer Implements
>> System.Collections.IComparer.Compare
>>
>> Dim returnVal As Integer = -1
>>
>> Dim xItem As System.Windows.Forms.ListViewItem = x
>> Dim yItem As System.Windows.Forms.ListViewItem = y
>>
>> If TypeOf CallerForm Is Demeter25.frmViewEditInactiveDocuments
>> Then
>> ' if the caller form is frmViewEditInactiveDocuments then
>> sort according the
>> ' columns in select case statement below
>> Select Case col
>> Case 0 ' in this case 0th column holds numerics
>> ' sort numeric values
>> Dim blnCompare As Boolean
>>
>> blnCompare = Val(xItem.SubItems(col).Text) >
>> Val(yItem.SubItems(col).Text)
>>
>> If blnCompare Then
>> returnVal = 1
>> Else
>> returnVal = -1
>> End If
>>
>> Case 1 ' in this case 1th column holds strings
>> ' sort strings
>> returnVal = [String].Compare(CType(x,
>> ListViewItem).SubItems(col).Text, CType(y,
>> ListViewItem).SubItems(col).Text)
>>
>> Case 2 '' in this case 2nd column holds datetime vals
>> ' sort date time values
>> returnVal =
>> DateTime.Compare(CDate(xItem.SubItems(col).Text),
>> CDate(yItem.SubItems(col).Text))
>>
>> Case 3 '' in this case 3rd column holds datetime
>> vals, too
>> ' sort date time values
>> returnVal =
>> DateTime.Compare(CDate(xItem.SubItems(col).Text),
>> CDate(yItem.SubItems(col).Text))
>>
>> Case 4 '' in this case 0th column holds numerics
>> ' sort numeric values
>> Dim blnCompare As Boolean
>>
>> blnCompare = Val(xItem.SubItems(col).Text) >
>> Val(yItem.SubItems(col).Text)
>>
>> If blnCompare Then
>> returnVal = 1
>> Else
>> returnVal = -1
>> End If
>>
>> Case Else
>>
>> End Select
>>
>>
>> ' is sort order descending
>> If order = SortOrder.Descending Then
>> ' ivert the value returned by string.compare.
>> returnVal *= -1
>> End If
>>
>> Return returnVal
>> End Function
>>
>> End Class
>> ---------END OF CLASS CODE----------------------------------------
>>
>> Now, in variable declaration part of your form add:
>> dim sortColumn as integer = -1 ' no sorting yet
>>
>> inside the lvwMyList_ColumnClick event add:
>> If e.Column <> sortColumn then
>> sortColumn = e.column
>> lvwMyList.Sorting = Sorting.Ascending ' asc by default
>>
>> if lvwMyList.Sorting = sortOrder.Ascending then
>> lvwMyList.Sorging = SortOrder.Descending
>> else
>> lvwMyList.Sorging = SortOrder.Ascending
>> end if
>>
>> lvwMyList.Sort()
>> lvwMyList.ListViewItemSorter = New clsSorter(e.Column,
>> lvwMyList.Sorting)
>>
>> end if
>>
>>
>> hope this helps,
>>
>> Dino
>>
>> On Mon, 15 Mar 2004 22:48:34 +0200, "Sameh Ahmed"
>> <essoplus@hotmail.com> wrote:
>>
>> >Excellent
>> >both worked fine:)
>> >now a another quick question if possible
>> >I set the tree view Sorting to Ascending
>> >what if I want it to be sorting depending on the column that the user
>clicks
>> >it's header
>> >Example:
>> >when he click the header column header of emplid it will be sorted by
>that
>> >column and so on?
>> >Thanks for your time
>> >Regards
>> >Sameh
>> >
>> >"Herfried K. Wagner [MVP]" <hirf-spam-me-here@gmx.at> wrote in message
>> >news:c352l9$22kfb0$2@ID-208219.news.uni-berlin.de...
>> >> * "Sameh Ahmed" <essoplus@hotmail.com> scripsit:
>> >> > Hello there
>> >> > I have a listview with 3 header columns, I can populate the first and
>> >second
>> >> > one with the following code, but cannot figure out how to populate
>the
>> >third
>> >> > and the following header columns?
>> >> > listview.Items.Add(empname)
>> >> > listview.Items(i).SubItems.Add(empid)
>> >>
>> >> The same as the line above. Add a 2nd 'SubItem' to 'Items(i)'.
>> >>
>> >> --
>> >> Herfried K. Wagner [MVP]
>> >> <http://dotnet.mvps.org/>
>> >
>>
>

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