topic Re: List GDB Feature Classes in ArcObjects SDK Questions

List GDB Feature Classes

DaveCouture — Thu, 19 Dec 2013 18:01:18 GMT

I'm using a VB.NET code found in the ESRI Resource Center to list the content of a GDB. For some reasons, it's not working. It hangs or I get an empty string value.

Here's my code:

Imports ESRI.ArcGIS.Geodatabase
Imports ESRI.ArcGIS.Carto
Imports ESRI.ArcGIS.esriSystem
Imports System.Windows.Forms
Imports ESRI.ArcGIS.Geoprocessing
Imports ESRI.ArcGIS.Geoprocessor      

Public Sub test()

        Dim gp As New ESRI.ArcGIS.Geoprocessor.Geoprocessor
        gp.SetEnvironmentValue("workspace", "G:\Data\GDB\Production.gdb")
        Dim fcs As ESRI.ArcGIS.Geoprocessing.IGpEnumList = gp.ListFeatureClasses("*", "", "")
        Dim fc As String = fcs.Next()

        Do While fc <> ""
            fc = fc + vbNewLine + fcs.Next()
        Loop

        MsgBox(fc)

End Sub

Re: List GDB Feature Classes

NeilClemmons — Thu, 19 Dec 2013 18:19:32 GMT

Your loop condition is to loop while fc is not an empty string. You're setting the value of fc inside the loop to an actual value, so it will never be an empty string. This results in an infinite loop because your loop condition will always be true. The only exception is when no feature class names are returned at all, in which case fc is an empty string to start with. In this case, you get the empty string. In the case of the infinite loop, you get the hang.

Re: List GDB Feature Classes

DaveCouture — Fri, 20 Dec 2013 11:23:58 GMT

Makes sense. But, this is the code I found here, in the ESRI Developer Network: http://edndoc.esri.com/arcobjects/9.2/NET/74749fb9-9724-465f-9e1c-32c6faec1d5e.htm

Re: List GDB Feature Classes

NeilClemmons — Sat, 11 Dec 2021 15:47:19 GMT

Actually, that's not the code you found there at all. The code at that link is this:

Do While fc <> ""

        Console.WriteLine(fc)
        fc = fcs.Next()

    Loop

You've modified that code to append the feature class name to the variable fc with each loop iteration. This is why fc will never be an empty string and why you a running into an infinite loop. The code at that link works because it assigns the feature class name to the variable fc instead of appending it. When fcs.Next() returns an empty string, fc will be assigned an empty string and the loop will terminate.

Re: List GDB Feature Classes

DaveCouture — Fri, 20 Dec 2013 13:35:51 GMT

OK, thanks! I'll create another string to append all the names.