topic Re: ComboBox to add layers from folder, selected from .txt list in same folder in ArcGIS Pro SDK Questions

ComboBox to add layers from folder, selected from .txt list in same folder

Dood345 — Thu, 09 Feb 2023 20:22:23 GMT

I think I've gotten close to getting this working but the function to read in the table stored in the .txt file can not read the table. I am probably using the wrong method, I'm using a FileSystemDatastore.OpenDataset(Of Table)(...).

Below is a sample of the list of layers .txt (organized like a .csv):

LayerName,Path
Annotation Text,DRIVE:\FileLocation\LayerFiles\ANNOTATION TEXT.lyr
-----Land & Property (Choose from items below)-----,NOTHING
...

Below is a sample of the first read in of the table/.txt:

Public Async Sub UpdateCombo()
Dim WorkspaceF As FileSystemDatastore
Dim FileConnection As FileSystemConnectionPath
Dim Table As Table
Dim Cur As RowCursor
Dim Row As Row
Dim GDBLocation As Uri
GDBLocation = New Uri("DRIVE:\FileLocation\LayerFiles\")
Try
Await QueuedTask.Run(Sub()
If Not File.Exists(FILE_NAME) Then
MsgBox("File Does Not Exist")
End If
FileConnection = New FileSystemConnectionPath(GDBLocation, FileSystemDatastoreType.Shapefile)
WorkspaceF = New FileSystemDatastore(FileConnection)
Table = WorkspaceF.OpenDataset(Of Table)("coa_LAYERS_list.txt")
MsgBox(Table.GetCount)
Cur = Table.Search(Nothing, False)
Cur.MoveNext()
Row = Cur.Current
Do Until Row Is Nothing
Add(New ComboBoxItem(Row.Item(0).ToString))
Cur.MoveNext()
Row = Cur.Current
Loop
Table = Nothing
Row = Nothing
WorkspaceF = Nothing
FileConnection = Nothing
Cur = Nothing
GC.Collect()
End Sub)

I do use " (QF.WhereClause = "LayerName = '" & Value & "'") " later but for now I'm just trying to figure out why the table is not being read.

Re: ComboBox to add layers from folder, selected from .txt list in same folder

NarelleChedzey — Thu, 09 Feb 2023 22:25:57 GMT

Hi,

Seeing you're reading just a .txt file - I would recommend using standard .NET read/write classes/methods to open your file rather than the FileSystemConnectionPath object.

https://learn.microsoft.com/en-us/dotnet/visual-basic/developing-apps/programming/drives-directories-files/how-to-read-text-from-files-with-a-streamreader

This link has a code snippet which seems to suit your situation - opening a text file and reading lines.

Thanks

Narelle

Re: ComboBox to add layers from folder, selected from .txt list in same folder

Dood345 — Tue, 21 Feb 2023 22:41:02 GMT

A bit late on the response but Exams in college got the better of me. I was trying to avoid that since my focus for this project was to learn more about the add-in API. That being said, I went ahead and swapped to using the basic library (visual basic), and just used a delimited line reader, worked great.

Now I can not for the life of me figure out why it won't add the layer. I have the "OnSelectionChange" method overwritten with

Protected Overridable Overloads Sub OnSelectionChange(layerName As ComboBoxItem)

 If (layerName.ToString = "") Then
     MsgBox("Could not read layer name" + layerName.ToString)
     Return
 End If

 MsgBox("getting layer file " + layerName.ToString)

 GetLayerFile(layerName.ToString)
 MyBase.OnSelectionChange(layerName)

End Sub

However neither msg box appears, and then GetLayerFile is

Public Sub GetLayerFile(ByVal layerName As String)

 Dim activeView As MapView
 activeView = MapView.Active

 If Not File.Exists(FILE_NAME) Then
     MsgBox("File Does Not Exist")
     Return
 End If

 Using lineReader As New Microsoft.VisualBasic.FileIO.TextFieldParser(FILE_NAME)

 lineReader.TextFieldType = FileIO.FieldType.Delimited
 lineReader.SetDelimiters(",")
 Dim lineFields As String()

  While Not lineReader.EndOfData
     Try
          lineFields = lineReader.ReadFields()
          If (lineFields(0) = layerName) Then
               AddLayerToActiveView(activeView, lineFields(1))
               MsgBox(lineFields(1))
          Return
          End If

     MsgBox("Could not find layer")

     Catch ex As Exception
     ' Let the user know what went wrong.
     MsgBox("The Layer Path Cannot be read: Line " & ex.Message & "is not valid and will be skipped.")
     Return

     End Try

   End While

 End Using

End Sub

I don't know if there's anything blaringly obvious, this is the AddLayerToActiveView method

Public Async Sub AddLayerToActiveView(ByVal activeView As MapView, ByVal layerPathFile As System.String) 
 Dim Path As Uri
 Path = New Uri(layerPathFile)

 Try
      Await QueuedTask.Run(Sub()
           LayerFactory.Instance.CreateLayer(Path, MapView.Active.Map)
      End Sub)
 Catch e As Exception
      ' Let the user know what went wrong.
      MsgBox("The Layer Path Cannot be read: code2")
      MsgBox(e.Message)

 End Try

Re: ComboBox to add layers from folder, selected from .txt list in same folder

NarelleChedzey — Thu, 23 Feb 2023 03:30:54 GMT

Hi,

Can you change the definition of your OnSelectionChange function to the following and see if that helps with the method firing when a choice is made in the combobox.

Protected Overrides Sub OnSelectionChange(layerName As ComboBoxItem)

(so it is Overrides not Overridable Overloads)

Narelle

Re: ComboBox to add layers from folder, selected from .txt list in same folder

Dood345 — Thu, 23 Feb 2023 16:27:24 GMT

I think that did it, now I just have to sort out my string comparison to identify the layers to add! Hopefully I'm good from here. Thank you, Narelle, for all the help.

I think I see why that was an issue, overridable overloads basically means that the method I wrote could be overridden and is just another overload for "onSelectionChange" so might not even be called since the program would just do a standard call not the overloaded version.