[RESOLVED] How fast should a Listview add 150 items

[jumper77]

I'm just trying to do a reality check. I'm loading 150 items into a Listview and it's taking about 3 seconds to do it. I'm loading all the files from a directory and getting their icons or bitmaps, then adding them to the Listview.

I've read that using "add.range" is faster, but I don't know how to do that with my code. Here's a bit of code so maybe you will understand better how I'm doing things...

            For Each FileInfo In dirInfo.GetFiles
                If FileInfo.Name = "Desktop.ini" Then Continue For

                filename = Path.Combine(DesktopPath, FileInfo.Name)

                If isLink(filename) Then
                    If IsDir(fileInfo) Then
                        bmp = CType(Customize.pb1.Image, Bitmap)

                        AddListviewItems(ImageList1, fileInfo, bmp)
                        i += GetOne
                        Continue For

                    End If

                    extension = Path.GetExtension(fileInfo.FullName)
                    If extension = ".lnk" Then
                        filename = Path.GetFileNameWithoutExtension(fileInfo.FullName)
                        extension = Path.GetExtension(filename)
                    End If

                    Select Case extension.ToLower
                        Case ".jpeg", ".jpg", ".pdf", ".png", ".gif", ".ico", ".mp3", ".mp4", ".db", ".csv",
                             ".xml", ".config", ".rtf", ".sys", ".bmp", ".wav", ".ani", ".r2skin", ".bat",
                             ".chm", ".adt", ".css", ".js", ".pkgdef", ".vssettings", ".resx", ".natvis",
                             ".cs", ".vstemplate", ".settings", ".vbproj", ".csproj", ".tt", ".xaml", ".ruleset",
                             ".xsd", ".xslt", ".wsf", ".cpp", ".h", ".props", ".targets", ".ttf", ".cat",
                             ".cmd", ".reg", ".c", ".inf", ".ts", ".mht", ".def", ".hpp", ".msi", ".idl",
                             ".vsix", ".mrimg", ".theme", ".msstyles", ".inc", ".psd1", ".psm1", ".ps1",
                             ".ps1xml", ".srt", ".aac", ".adt", ".adts", ".accdb", ".accde", ".accdr", ".accdt",
                             ".aif", ".aifc", ".aiff", ".aspx", ".avi", ".cda", ".dif", ".doc", ".docm", ".docx",
                             ".dotx", ".eml", ".eps", ".iso", ".jar", ".m4a", ".mdb", ".mid", ".midi", ".mov",
                             ".mpeg", ".mpg", "potm", "potx", ".ppam", ".ppsm", ".ppsx", ".pptm", ".pptx",
                            ".psd", ".pst", ".pub", ".sldx", ".swf", ".wma", ".wmv", ".xla", ".xlam", ".xlsm",
                            ".xlsmx", ".xltm", ".xltx", ".xps", ".sql", ".fnt", ".fon", ".otf", ".tif", ".tiff",
                            ".asp", ".jsp", ".part", ".php", ".xhtml", ".opd", ".pps", ".ppt", ".class", ".java",
                            ".ods", ".xlr", ".xls", ".xlsx", ".cur", ".adp", ".cpl", ".sfx"

                            AddListviewItems(ImageList1, fileInfo, GetBitmap(fileInfo))

                            i += GetOne
                            Continue For

                        Case ".zip", ".7z", ".rar"
                            AddListviewItems(ImageList1, fileInfo, GetZipBitmap(fileInfo))
                            i += GetOne
                            Continue For

                        Case ".pdf"
                            AddListviewItems(ImageList1, fileInfo, GetBitmap(fileInfo))
                            i += GetOne
                            Continue For

                        Case ".txt", ".log", ".md"
                            AddListviewItems(ImageList1, fileInfo, GetTextIcon())
                            i += GetOne
                            Continue For

                        Case Else
                            Try
                                AddListviewItems(ImageList1, fileInfo, GetBitmap(fileInfo))
                                i += GetOne
                                Continue For
                            Catch ex As Exception
                                MsgBox(ex.Message)
                            End Try


                            If extension <> ".dll" Then
                                AddListviewItems(ImageList1, fileInfo, My.Resources.RedQuestion)
                                i += GetOne
                                Continue For
                            End If

                            extension = Path.GetExtension(fileInfo.FullName).ToLower
                            If extension = ".lnk" Then
                                extension = Path.GetFileNameWithoutExtension(fileInfo.FullName)
                            End If
                            If extension.Contains("(") Then
                                filename = filename.Substring(0, filename.Length - 4)
                            End If
                            If extension <> ".zip" And extension <> ".7z" And extension <> ".rar" Then

                                If Path.GetExtension(fileInfo.FullName).ToLower <> ".bmp" Then
                                    Dim key As String = GetAssociatedProgram(Path.GetExtension(fileInfo.FullName).ToLower)
                                    If key = vbNullString And (Path.GetExtension(fileInfo.FullName.ToLower) <> ".exe") Then
                                        ' this catches files that are not associated with a program...
                                        Try
                                            If Not AddListviewItems(ImageList1, fileInfo, GetBitmap(fileInfo)) Then
                                                myIcon = ExtractIcon(fileInfo)
                                                AddListviewItems(ImageList1, fileInfo, myIcon.ToBitmap)

                                                i += GetOne 'new

                                                If myIcon IsNot Nothing Then myIcon.Dispose()
                                                Continue For
                                            End If
                                        Catch ex As Exception
                                            While myIcon IsNot Nothing
                                                myIcon.Dispose()
                                            End While
                                            Continue For
                                        End Try
                                    Else
                                        myIcon = ExtractIcon(fileInfo)
                                        AddListviewItems(ImageList1, fileInfo, myIcon.ToBitmap)

                                        If myIcon IsNot Nothing Then myIcon.Dispose()
                                        Continue For
                                    End If
                                End If
                            End If
                    End Select
...

There's more code, but just wanted to give you enough to understand how I'm doing things. To me, 3 seconds seems slow and I would like to make it faster if I can. With the code I have, how can I use Add Range?

Thanks in advance for any help...

[.paul.]

Instead of adding each item to your listview one by one, add them to a List(of ListViewItem). When you have added all of your items to the list...

ListView1.Items.AddRange(yourList.ToArray())

[.paul.]

Have a look at the different overloads for creating a ListViewItem, and adding imageindex using With...

[.paul.]

The problem with your code is that the ListView repaints every time you add an item, using AddRange it just repaints once

[peterst]

You can also add before and after the loop ListView.BeginUpdate and ListView.EndUpdate calls so it will not repaint on each added item.

[jumper77]

Thank you Paul, I will see if I can get the List working. And thank you peterst, I am using the begin and end update.

[jumper77]

Don't give me the answer yet... I think I almost have it figured out, lol

[jumper77]

I take that back... didn't work

[.paul.]

Ok. What does each item contain? Can you post your AddListviewItems code? Addrange should be no problem...

[jumper77]

Sure, it's a bit big though...

    Private Function AddListviewItems(imgList As ImageList, fi As FileInfo, Optional bmp As Bitmap = Nothing,
                                      Optional thisIcon As Icon = Nothing) As Boolean

        Dim extension As String = vbNullString
        Dim filename As String = vbNullString
        Dim NormalFilename As String = vbNullString
        Dim fullpathtoFile As String = vbNullString

        If fi Is Nothing Then Return False

        If Path.GetExtension(fi.FullName).ToLower = ".lnk" Then
            If bmp IsNot Nothing Then
                If IsDir(fi) Then
                    If bmp IsNot Nothing Then
                        If IsDir(fi) Then
                            If bmp IsNot Nothing Then
                                imgList.Images.Add(fi.FullName, bmp)
                                ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName
                                Return True
                            End If
                        End If

                        imgList.Images.Add(fi.FullName, bmp)
                        ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

                        If bmp IsNot Nothing Then bmp.Dispose()
                        Return True
                    End If
                Else
                    If bmp IsNot Nothing Then
                        Try
                            imgList.Images.Add(fi.FullName, bmp)
                            ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

                            If bmp IsNot Nothing Then bmp.Dispose()
                        Catch ex As Exception
                            MsgBox("Error on file: " & fi.Name & " error is: " & ex.Message)
                        End Try
                        Return True
                    End If
                End If

                imgList.Images.Add(fi.FullName, bmp)
                ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

                If bmp IsNot Nothing Then bmp.Dispose()
                Return True
            Else
                If thisIcon IsNot Nothing Then
                    imgList.Images.Add(fi.FullName, thisIcon.ToBitmap)
                    ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

                    If thisIcon IsNot Nothing Then thisIcon.Dispose()
                    Return True
                End If
            End If
        Else
            extension = Path.GetExtension(fi.FullName).ToLower
            Select Case extension
                Case ".zip", ".7z", ".rar"
                    imgList.Images.Add(fi.FullName, bmp)
                    ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

                    If bmp IsNot Nothing Then bmp.Dispose()
                    Return True
                Case Else

                    If thisIcon IsNot Nothing Then
                        imgList.Images.Add(fi.FullName, thisIcon.ToBitmap)
                        ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

                        If thisIcon IsNot Nothing Then thisIcon.Dispose()
                        Return True
                    Else
                        If bmp IsNot Nothing Then
                            imgList.Images.Add(fi.FullName, bmp)
                            ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

                            If bmp IsNot Nothing Then bmp.Dispose()
                            Return True
                        End If
                    End If
            End Select
        End If

        'extension = Path.GetExtension(fi.FullName).ToLower
        If extension = ".txt" Then

            imgList.Images.Add(fi.FullName, bmp)
            ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

            If bmp IsNot Nothing Then bmp.Dispose()
            Return True
        Else
            Select Case extension.ToLower
                Case ".png", ".zip", ".vb"

                Case Else
                    If bmp IsNot Nothing Then
                        imgList.Images.Add(fi.FullName, bmp)
                        ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName
                    Else
                        imgList.Images.Add(fi.FullName, thisIcon)
                        ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName
                    End If

                    If bmp IsNot Nothing Then bmp.Dispose()
                    Return True
            End Select
        End If

        If Path.GetExtension(fi.FullName).ToLower = ".pdf" Then
            If thisIcon IsNot Nothing Then
                imgList.Images.Add(fi.FullName, Customize.PictureboxPDF.Image)
                ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

                If thisIcon IsNot Nothing Then thisIcon.Dispose()
                Return True
            Else
                imgList.Images.Add(fi.FullName, thisIcon)
                ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

                Return True
            End If
        End If

        If Path.GetExtension(fi.FullName).ToLower = ".png" Then
            imgList.Images.Add(fi.FullName, bmp)
            ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

            If bmp IsNot Nothing Then bmp.Dispose()
            Return True
        End If

        extension = Path.GetExtension(fi.FullName).ToLower
        If extension = ".vb" Then
            imgList.Images.Add(fi.FullName, thisIcon)
            ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

            If thisIcon IsNot Nothing Then thisIcon.Dispose()
            Return True
        End If

        If Path.GetExtension(fi.FullName).ToLower = ".zip" Or Path.GetExtension(fi.FullName).ToLower = ".7z" _
                 Or Path.GetExtension(fi.FullName).ToLower = ".rar" Then

            If isLink(fi.FullName) Then
                imgList.Images.Add(fi.FullName, bmp)
                ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

                If bmp IsNot Nothing Then bmp.Dispose()
                Return True
            Else
                imgList.Images.Add(fi.FullName, bmp)
                ListView1.Items.Add(Trimfilename(fi), fi.FullName).Tag = fi.FullName

                If bmp IsNot Nothing Then bmp.Dispose()
                Return True
            End If
        End If

        Return False

    End Function

Edit: Please overlook the first part of the code. While it does work, I just now noticed how "nuts" it is, lol. Must have been a late night when I wrote that...

[.paul.]

Try the List(of ListViewItem) I suggested...
Declare the List at Form level. To add an item...

YourList.Add(New ListViewItem(New String() {aString, anotherString, etc}) With {.Tag = whatever, .ImageIndex = anInteger})

[jumper77]

Thanks, will check that out...

[jumper77]

I've never need to get an index from an ImageList before, but here's what I'm trying...

       myIndex = imgList.Images.IndexOfKey(fi.FullName)
       DoList.Add(New ListViewItem(New String() {filename}) _
                        With {.Tag = fi.FullName, .ImageIndex = myIndex})

MyIndex is returning 7 (which sounds about right), but when I hover over ".Tag" it says the value is "Nothing". However if I hover over "fi.fullname", it does have the value it should.

Is this the right way to get an index?

[.paul.]

Sorry autocorrect error... edited

Try Loading the full list, then adding it to the ListView as I showed you...

ListView1.Items.AddRange(DoList.ToArray())

It looks like you’re testing the tag with execution stopped before that line is executed. Try putting the breakpoint after that line...

[jumper77]

Oops, I think you are right about me having it on the breakpoint. I have defined "DoList" at the from level and I'm using the same code you put in your last message. But the item doesn't show up in the list view.

In a way it's kind of a special case. It's a link to a folder. I'm going to try it with a regular file and see what happens

[jumper77]

I almost have it. Give me a few minutes and I'll show you what I did...

[.paul.]

If your ListView View isn’t details, looks like you’re using icons? That’d be a slightly different overload of the ListViewItem...

[jumper77]

I "think" I have it working. At least on some items.
Here's what the code is now...

        Try
            imgList.Images.Add(fi.FullName, bmp)
            filename = Path.GetFileNameWithoutExtension(fi.Name)

            myIndex = imgList.Images.IndexOfKey(fi.FullName)
            DoList.Add(New ListViewItem(New String() {filename}) _
                             With {.Tag = fi.FullName, .ImageIndex = myIndex})

            If bmp IsNot Nothing Then bmp.Dispose()
            
            Catch ex As Exception
                 MsgBox("Error on file: " & fi.Name & " error is: " & ex.Message)
            End Try

Then at the end of the calling sub...

   ListView1.Items.AddRange(DoList.ToArray())

[.paul.]

If your ListView View isn’t details, looks like you’re using icons? That’d be a slightly different overload of the ListViewItem...

[.paul.]

Have a look at...

ListViewItem(String, Int32)

Instead of...

ListViewItem(String())

https://docs.microsoft.com/en-us/dot..._System_Int32_

[.paul.]

DoList.Add(New ListViewItem(filename, myIndex) With {.Tag = fi.FullName})

[jumper77]

However, it's taking just as long to go through all the files. I'm pretty sure adding Images is what's taking up the time now. And I don't know how to get to the bitmap (or index) without adding the images.

[.paul.]

Where are the images coming from? You do know you can load an image list at design time, right?

[.paul.]

Are they file icons? I’m not sure how you can significantly speed that up with a dynamic list of files

[jumper77]

Yes they are file icons. Can't do it at design time because I never know what file will be in the directory. I've been trying everything I can find to speed up the code, and I've been doing it for a while now. It may end up being that "this is as fast as it's going to get".

But because I'm stubborn, I will keep looking for was to speed things up. This is the last major issue I have to deal with with my program. Sure would love to find a way to make it faster, lol.

We can give up on this one, if you want. I'll just keep looking...

[jumper77]

If your ListView View isn’t details, looks like you’re using icons? That’d be a slightly different overload of the ListViewItem...

The view is LIST

[.paul.]

Yeah i read the earlier posts in this thread. The only way you can significantly increase the speed of loading 150 icons is to load them into your imagelist at design time. The icons are definitely the slow part...

[.paul.]

The imagelist key could just be the extension...

[jumper77]

Ok then. I really appreciate all the help Paul. I did learn something thanks to you. Thanks a bunch. If I ever find a work around, I'll let you know about it. I'm going to mark this as "resolved".

[jumper77]

The imagelist key could just be the extension...

I don't understand what you mean?

[.paul.]

At the moment, you’re using the filename. If you had a preloaded imagelist, the txt icon would have the key .txt instead of filename.txt

[jumper77]

This may sound dumb, but how could I have a "preloaded" ImageList for items that are unknown?

[jumper77]

I changed the number of items in the Listview to 75 and now it loads in 1.4 seconds

[jumper77]

But I do agree about the preloaded ImageList. I'm sure it would be much faster

[.paul.]

This may sound dumb, but how could I have a "preloaded" ImageList for items that are unknown?

You know the basic file types, even if you don’t have a 100% loaded imagelist, it’d still be faster only downloading 1 or 2 instead of all of the icons. Just a suggestion, but I don’t see it being quicker any other way. You know the windows file explorer is a just-in-time implementation. Only the folders navigated to are loaded as and if needed. You might be able to do something along those lines...

[.paul.]

Not downloading... reading. I’m suggesting you extract all of your images with a small program written purely for that, then load your imagelist at design time from the images you’ve extracted previously. If you click on your imagelist at design time, check the properties. You can add images either at design time, or programmatically as your current code does.

[jumper77]

Not downloading... reading. I’m suggesting you extract all of your images with a small program written purely for that, then load your imagelist at design time from the images you’ve extracted previously. If you click on your imagelist at design time, check the properties. You can add images either at design time, or programmatically as your current code does.

I hope I'm not frustrating you too much because I am being a bit dumb about this. My apologies. Are you saying that if I create an ImageList at design time and "don't" add any images at design time, it would make for faster reading by the program?

But I don't think that's what you mean. Since every file has it's own unique Icon, I see of no way to add anything at design time.

Here's one of my functions for getting a file's bitmap. Maybe that will help both of us

   Private Function GetBitmap(fi As FileInfo) As Bitmap
        Dim filename As String = vbNullString
        Dim bmp As Bitmap
        Dim ret As Object
        Dim extension As String = vbNullString

        ret = rk.GetValue("BitmapIconPath")
        If CStr(ret) <> "" Then
            Return New Bitmap(CStr(ret))
        Else
            extension = Path.GetExtension(fi.FullName)
            filename = ResolveShortcut(fi.FullName)

            If IsDir(fi) Then
                Return CType(Customize.pb1.Image, Bitmap)
            End If

            If filename <> "" Then
                'extension = Path.GetExtension(filename)
                Select Case extension.ToLower
                    Case ".exe"
                        Using myIcon As Icon = ExtractIcon(fi)
                            Return myIcon.ToBitmap
                        End Using

                    Case Else
                        Try
                            Using thisbmp As Bitmap = New Bitmap(16, 16, PixelFormat.Format16bppRgb555)
                                tmpbmp = thisbmp
                                tmpbmp = Image.FromFile(filename)
                                Return CType(tmpbmp, Bitmap)
                            End Using
                        Catch ex As Exception
                            Using myIcon As Icon = ExtractIcon(fi)
                                Return myIcon.ToBitmap
                            End Using
                        End Try
                        Return bmp
                End Select
            Else
                extension = Path.GetExtension(fi.Name)
                Select Case extension.ToLower
                    Case ".ico"
                        Using myIcon As Icon = ExtractIcon(fi)
                            Return myIcon.ToBitmap
                        End Using
                    Case Else
                        filename = Path.GetFileName(fi.FullName)

                        Dim FirstParam As String = filename.Substring(filename.Length - 3, 1)
                        Dim SecondParam As String = filename.Substring(filename.Length - 1, 1)

                        If FirstParam = "(" And SecondParam = ")" Then
                            extension = filename.Substring(filename.Length - 8, 4)
                            filename = fi.FullName.Substring(0, fi.FullName.Length - 4)

                            Select Case extension.ToLower
                                Case ".png"
                                    Dim thisbmp As Bitmap = New Bitmap(24, 24, PixelFormat.Format16bppRgb555)
                                    thisbmp = CType(Image.FromFile(fi.FullName), Bitmap)
                                    Return thisbmp
                            End Select
                        Else
                            Try
                                filename = fi.FullName
                                filename = ResolveShortcut(filename)
                                Using Newbmp As Bitmap = New Bitmap(16, 16, PixelFormat.Format16bppRgb555)
                                    tempBmp = Newbmp
                                    If filename <> "" Then
                                        tempBmp = Image.FromFile(Path.Combine(DesktopPath, filename))
                                    Else
                                        tempBmp = Image.FromFile(Path.Combine(DesktopPath, fi.Name))
                                    End If

                                    Return CType(tempBmp, Bitmap)
                                End Using
                            Catch ex As Exception
                                Using myIcon As Icon = ExtractIcon(fi)
                                    If myIcon Is Nothing Then
                                        Return My.Resources.RedQuestion
                                    Else
                                        Return myIcon.ToBitmap
                                    End If
                                End Using
                            End Try
                        End If
                End Select
            End If

            Return Nothing
        End If
    End Function

I also allow the user to customize icons for certain extensions (like zip files). I have a directory for each of those file types that contain about 20 images they can select from (or than can add their own). And they can also just use the default image.

The customized image choices are stored in the registry and close to the top of the function, you can see where I'm trying to get those variables.

Don't know if any of this helps, but I hope it does. Let me know one way or another and I will close this item if you think we should

[PlausiblyDamp]

Might be worth having a look at https://docs.microsoft.com/en-us/vis.../?view=vs-2019 to see where the problem lies.

Personally I suspect it is the GetBitmap function but unless you do some profiling you are really guessing at the problem. Once you have performance monitored the app and identified the bottleneck then you can start to look at how to address the issue e,g, caching bitmaps, multi-threading, etc.

[jumper77]

I have to agree with you. And thanks for the link. I will check it out. I'm going to mark this as resolved and if something comes up later, I will start a new thread.

[jumper77]

One last update. I got the time down to 1.8 seconds for 100 items. And I think I can live with that. Also, I don't think there are too many people who have that many items on their desktop