|
web
newsgroups
|
|||||||||||||||||||||||
|
|||||||||||||||||||||||
Need to sort ListView columns that contain datesSome columns contain dates and others contain integers. What I did once before is in the Compare method I tried date and if that failed I did Integer. Seems kinda not nice - is there a better way? Thanks Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer Implements IComparer.Compare -snip ''Cast the objects to be compared to ListViewItem objects. lListviewX = CType(x, ListViewItem) lListviewY = CType(y, ListViewItem) Try 'Parse the two objects passed as a parameter as a DateTime. Dim lFirstDate As System.DateTime = DateTime.Parse(lListviewX.SubItems(mColumnToSort).Text) Dim lSecondDate As System.DateTime = DateTime.Parse(lListviewY.SubItems(mColumnToSort).Text) 'Compare the two dates. lCompareResult = DateTime.Compare(lFirstDate, lSecondDate) ' Catch 'If neither compared object has a valid date format compare the two items as a string lCompareResult = mInsensitiveCompare.Compare(lListviewX.SubItems(mColumnToSort).Text, lListviewY.SubItems(mColumnToSort).Text) 'Or can do this End Try Can´t you know in advance which is the data type of each column? If not then
you have to guess it, but I would do that before comparing, that is, take the first listitem, guess if the column contains date or integer and then call a different comparer for each case. -- Show quoteHide quoteBest regards, Carlos J. Quintero MZ-Tools: Productivity add-ins for Visual Studio .NET, VB6, VB5 and VBA You can code, design and document much faster. Free resources for add-in developers: http://www.mztools.com " **Developer**" <REMOVEdevelo***@a-znet.com> escribió en el mensaje news:emKtsqqeFHA.228@TK2MSFTNGP12.phx.gbl... >I need to sort the columns of a ListView. > > Some columns contain dates and others contain integers. > > What I did once before is in the Compare method I tried date and if that > failed I did Integer. > > Seems kinda not nice - is there a better way? > > Thanks > Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer > Implements IComparer.Compare > > -snip > > ''Cast the objects to be compared to ListViewItem objects. > > lListviewX = CType(x, ListViewItem) > > lListviewY = CType(y, ListViewItem) > > Try > > 'Parse the two objects passed as a parameter as a DateTime. > > Dim lFirstDate As System.DateTime = > DateTime.Parse(lListviewX.SubItems(mColumnToSort).Text) > > Dim lSecondDate As System.DateTime = > DateTime.Parse(lListviewY.SubItems(mColumnToSort).Text) > > 'Compare the two dates. > > lCompareResult = DateTime.Compare(lFirstDate, lSecondDate) > > ' Catch > > 'If neither compared object has a valid date format compare the two items > as a string > > lCompareResult = > mInsensitiveCompare.Compare(lListviewX.SubItems(mColumnToSort).Text, > lListviewY.SubItems(mColumnToSort).Text) 'Or can do this > > End Try > > > This is a generally used usercontrol so that would be difficult unless I
required the form containing the control to do something to help. Can't I get the type in the method somehow? Thanks Show quoteHide quote "Carlos J. Quintero [.NET MVP]" <carlosq@NOSPAMsogecable.com> wrote in message news:O$yJbPveFHA.2180@TK2MSFTNGP12.phx.gbl... > Can´t you know in advance which is the data type of each column? If not > then you have to guess it, but I would do that before comparing, that is, > take the first listitem, guess if the column contains date or integer and > then call a different comparer for each case. > > -- > Best regards, > > Carlos J. Quintero > > MZ-Tools: Productivity add-ins for Visual Studio .NET, VB6, VB5 and VBA > You can code, design and document much faster. > Free resources for add-in developers: > http://www.mztools.com > > " **Developer**" <REMOVEdevelo***@a-znet.com> escribió en el mensaje > news:emKtsqqeFHA.228@TK2MSFTNGP12.phx.gbl... >>I need to sort the columns of a ListView. >> >> Some columns contain dates and others contain integers. >> >> What I did once before is in the Compare method I tried date and if that >> failed I did Integer. >> >> Seems kinda not nice - is there a better way? >> >> Thanks >> Public Function Compare(ByVal x As Object, ByVal y As Object) As Integer >> Implements IComparer.Compare >> >> -snip >> >> ''Cast the objects to be compared to ListViewItem objects. >> >> lListviewX = CType(x, ListViewItem) >> >> lListviewY = CType(y, ListViewItem) >> >> Try >> >> 'Parse the two objects passed as a parameter as a DateTime. >> >> Dim lFirstDate As System.DateTime = >> DateTime.Parse(lListviewX.SubItems(mColumnToSort).Text) >> >> Dim lSecondDate As System.DateTime = >> DateTime.Parse(lListviewY.SubItems(mColumnToSort).Text) >> >> 'Compare the two dates. >> >> lCompareResult = DateTime.Compare(lFirstDate, lSecondDate) >> >> ' Catch >> >> 'If neither compared object has a valid date format compare the two items >> as a string >> >> lCompareResult = >> mInsensitiveCompare.Compare(lListviewX.SubItems(mColumnToSort).Text, >> lListviewY.SubItems(mColumnToSort).Text) 'Or can do this >> >> End Try >> >> >> > > No, the type is text always, so you must guess its format.
-- Show quoteHide quoteBest regards, Carlos J. Quintero MZ-Tools: Productivity add-ins for Visual Studio .NET, VB6, VB5 and VBA You can code, design and document much faster. Free resources for add-in developers: http://www.mztools.com " **Developer**" <REMOVEdevelo***@a-znet.com> escribió en el mensaje news:e4Ga%23OxeFHA.228@TK2MSFTNGP12.phx.gbl... > This is a generally used usercontrol so that would be difficult unless I > required the form containing the control to do something to help. > > Can't I get the type in the method somehow? > > Thanks > Now that I think of it that makes sense
Thanks Show quoteHide quote "Carlos J. Quintero [.NET MVP]" <carlosq@NOSPAMsogecable.com> wrote in message news:eb8%23xSxeFHA.3280@TK2MSFTNGP09.phx.gbl... > No, the type is text always, so you must guess its format. > > -- > Best regards, > > Carlos J. Quintero > > MZ-Tools: Productivity add-ins for Visual Studio .NET, VB6, VB5 and VBA > You can code, design and document much faster. > Free resources for add-in developers: > http://www.mztools.com > > " **Developer**" <REMOVEdevelo***@a-znet.com> escribió en el mensaje > news:e4Ga%23OxeFHA.228@TK2MSFTNGP12.phx.gbl... >> This is a generally used usercontrol so that would be difficult unless I >> required the form containing the control to do something to help. >> >> Can't I get the type in the method somehow? >> >> Thanks >> > On Mon, 27 Jun 2005 14:35:07 +0200, "Carlos J. Quintero [.NET MVP]"
<carlosq@NOSPAMsogecable.com> wrote: >No, the type is text always, so you must guess its format. You could always inherit from the list view and extend the columnsproperty by having the column type as an attribute and then call the appropriate comparator. I had a similar issue with a list view that shows information from a database table, here I used the column index returned on the column header click event and used that to refer into the datatable and find out what the database definition of that column's type was. Doug Taylor Hi Doug,
I know what you mean, but that would require some collaboration from the user of the usercontrol, wouldn´t it? I mean, if the user passes or uses the classes of the listview instead of the extended ones from the inherited listview... -- Show quoteHide quoteBest regards, Carlos J. Quintero MZ-Tools: Productivity add-ins for Visual Studio .NET, VB6, VB5 and VBA You can code, design and document much faster. Free resources for add-in developers: http://www.mztools.com "Doug Taylor" <Doug.TaylorNTP@tayNOSPAMmade.demon.co.uk> escribió en el mensaje news:0620c1lbh32pjq6b7nn5o0gg4b7omatun6@4ax.com... > On Mon, 27 Jun 2005 14:35:07 +0200, "Carlos J. Quintero [.NET MVP]" > <carlosq@NOSPAMsogecable.com> wrote: > > You could always inherit from the list view and extend the columns > property by having the column type as an attribute and then call the > appropriate comparator. > > I had a similar issue with a list view that shows information from a > database table, here I used the column index returned on the column > header click event and used that to refer into the datatable and find > out what the database definition of that column's type was. > > Doug Taylor > "Carlos J. Quintero [.NET MVP]" <carlosq@NOSPAMsogecable.com> wrote in Good point, I'd have to check to be sure I have a type stored for the column message news:OOYrJYyeFHA.3808@TK2MSFTNGP14.phx.gbl... > Hi Doug, > > I know what you mean, but that would require some collaboration from the > user of the usercontrol, wouldn´t it? I mean, if the user passes or uses > the classes of the listview instead of the extended ones from the > inherited listview... and if not do what I'm doing now. I'm assuming one of the problems whith using Try-Catch is that it is slow. Is that right?? With or without Doug's suggestion, Would it be better if when the routine is entered it checks to see if a type is stored for that column and if not figure it out and store it. Then Select case storedTypeForColumn(..) case int case string .. .. .. That way it would only check once per column. " **Developer**" <REMOVEdevelo***@a-znet.com> escribió en el mensaje Yes, exceptions should be avoided, but if you do it only once it is fine.news:%23Ph%23TuyeFHA.3712@TK2MSFTNGP09.phx.gbl... > I'm assuming one of the problems whith using Try-Catch is that it is > slow. Is that right?? > With or without Doug's suggestion, That's error prone. For example, you get "1": is it a string or an integer > Would it be better if when the routine is entered it checks to see if a > type is stored for that column and if not figure it out and store it. number? You may guess that it is a number. Later you get "1.1" for that same column -> the type is likely to be float number...or you get "A" -> the type was not an integer number, it was a string after all... -- Best regards, Carlos J. Quintero MZ-Tools: Productivity add-ins for Visual Studio .NET, VB6, VB5 and VBA You can code, design and document much faster. Free resources for add-in developers: http://www.mztools.com
Show quote
Hide quote
"Carlos J. Quintero [.NET MVP]" <carlosq@NOSPAMsogecable.com> wrote in Actually I did think about that.message news:OWxpGLzeFHA.1448@TK2MSFTNGP14.phx.gbl... > > " **Developer**" <REMOVEdevelo***@a-znet.com> escribió en el mensaje > news:%23Ph%23TuyeFHA.3712@TK2MSFTNGP09.phx.gbl... >> I'm assuming one of the problems whith using Try-Catch is that it is >> slow. Is that right?? > > Yes, exceptions should be avoided, but if you do it only once it is fine. > > >> With or without Doug's suggestion, >> Would it be better if when the routine is entered it checks to see if a >> type is stored for that column and if not figure it out and store it. > > That's error prone. For example, you get "1": is it a string or an integer > number? You may guess that it is a number. Later you get "1.1" for that > same column -> the type is likely to be float number...or you get "A" -> > the type was not an integer number, it was a string after all... > > > -- As long as I'm giving the user a way of telling, I'll probably just assume string if not told. Thanks again "Doug Taylor" <Doug.TaylorNTP@tayNOSPAMmade.demon.co.uk> wrote in message I think that will work niceky. I already have a ColumnAdd method and will news:0620c1lbh32pjq6b7nn5o0gg4b7omatun6@4ax.com... > On Mon, 27 Jun 2005 14:35:07 +0200, "Carlos J. Quintero [.NET MVP]" > <carlosq@NOSPAMsogecable.com> wrote: > >>No, the type is text always, so you must guess its format. > > You could always inherit from the list view and extend the columns > property by having the column type as an attribute and then call the > appropriate comparator. > simply insert an optional type parameter. Thanks alot Show quoteHide quote > I had a similar issue with a list view that shows information from a > database table, here I used the column index returned on the column > header click event and used that to refer into the datatable and find > out what the database definition of that column's type was. > > Doug Taylor > I could develop a enum for the different types but I wonder if there is
already something I could use? That is: Public Sub ColumnAdd(ByVal header As String......,optional byval columnType as ???=string) Show quoteHide quote " **Developer**" <REMOVEdevelo***@a-znet.com> wrote in message news:OBac1cyeFHA.3280@TK2MSFTNGP09.phx.gbl... > > "Doug Taylor" <Doug.TaylorNTP@tayNOSPAMmade.demon.co.uk> wrote in message > news:0620c1lbh32pjq6b7nn5o0gg4b7omatun6@4ax.com... >> On Mon, 27 Jun 2005 14:35:07 +0200, "Carlos J. Quintero [.NET MVP]" >> <carlosq@NOSPAMsogecable.com> wrote: >> >>>No, the type is text always, so you must guess its format. >> >> You could always inherit from the list view and extend the columns >> property by having the column type as an attribute and then call the >> appropriate comparator. >> > > I think that will work niceky. I already have a ColumnAdd method and will > simply insert an optional type parameter. > > Thanks alot > > > > >> I had a similar issue with a list view that shows information from a >> database table, here I used the column index returned on the column >> header click event and used that to refer into the datatable and find >> out what the database definition of that column's type was. >> >> Doug Taylor >> > > You can use System.TypeCode
-- Show quoteHide quoteBest regards, Carlos J. Quintero MZ-Tools: Productivity add-ins for Visual Studio .NET, VB6, VB5 and VBA You can code, design and document much faster. Free resources for add-in developers: http://www.mztools.com " **Developer**" <REMOVEdevelo***@a-znet.com> escribió en el mensaje news:%231MyejyeFHA.3280@TK2MSFTNGP09.phx.gbl... >I could develop a enum for the different types but I wonder if there is >already something I could use? > > That is: > > Public Sub ColumnAdd(ByVal header As String......,optional byval > columnType as ???=string) > "Carlos J. Quintero [.NET MVP]" <carlosq@NOSPAMsogecable.com> wrote in Thanksmessage news:ePA13MzeFHA.688@TK2MSFTNGP14.phx.gbl... > You can use System.TypeCode 
Other interesting topics
Accessing dlls at runtime
C# to VB crossover questions hide control based on SQLS2K column level permission Update Element in ArrayList Structure GetType and ApplicationClass About MessageQueue Problem Large fonts setting (120DPI) Public vs Shared Using JPG stills to make a "Video" file c# to vb.net converter |
|||||||||||||||||||||||
