How do I read the custom string fields of an Entry in keepass?

Question

I am using the vanilla library of keepass simply by adding the .exe file to my project. From my code I am accessing PwDatabase like so:

var dbpath = @"\\MyPath\To\PersonalVault\PersonalVault.kdbx";
var masterpw = "myPassword";

var ioConnInfo = new IOConnectionInfo { Path = dbpath };
var compKey = new CompositeKey();
compKey.AddUserKey(new KcpPassword(masterpw));

var db = new KeePassLib.PwDatabase();
db.Open(ioConnInfo, compKey, null);

From there I want to access and read the custom string field that I have previously manually added from the Advanced tab of entry on the UI:

var entry = db.RootGroup.FindEntry(new KeePassLib.PwUuid(KeePassLib.Utility.MemUtil.HexStringToByteArray("97A51FE92F700D4FB665DC6AA7C9D67D")), true);
var customString = entry.Strings.Where(lookingFor => lookingFor.Key.Equals("customString")).FirstOrDefault().Value;

However I end up with a null value here.

Any suggestion on how I can read this or is it simply not exposed through the vanilla KeePass.exe?

SwaroSh · Accepted Answer · 2021-07-28T07:45:20.533

The "Entry" tab on KeePass.exe UI shows data stored in PwEntry (KeePass source code is downloadable here) with reserved key names. Reserved key names are shown in code sample below.

The "Advanced" tab on KeePass.exe UI stores strings with custom key names. So, when reading them in code, entry.Strings.ReadSafe("myCustomString") works (assuming that a custom string with that key name is present in the password entry). Below is the code that I tried and it works.

        var pwUuid = new KeePassLib.PwUuid(KeePassLib.Utility.MemUtil.HexStringToByteArray("F3A8DC6E93571944B485AA947C68FB5E"));
        var entry = db.RootGroup.FindEntry(pwUuid, true);
            
        // Reserved key names ("Entry" tab on KeyPass.exe)
        Console.WriteLine($"Title   : {entry.Strings.ReadSafe("Title")}");
        Console.WriteLine($"UserName: {entry.Strings.ReadSafe("UserName")}");
        Console.WriteLine($"Password: {entry.Strings.ReadSafe("Password")}");
        Console.WriteLine($"URL     : {entry.Strings.ReadSafe("URL")}");
        Console.WriteLine($"Notes   : {entry.Strings.ReadSafe("Notes")}");

        // Custom key names ("Advanced" tab on KeePass.exe)
        Console.WriteLine($"myCustomString: {entry.Strings.ReadSafe("myCustomString")}");

This also made me wonder about clashes between reserved and custom key names. As expected KeePass.exe UI does show an error if I try to create a custom key with a reserved key name.

I dont think this is it, the custom strings Im talking about are on the entry level. This CustomData field seems to be on database level. — Vrankela, Jul 21 '21 at 15:01
Agree. PwEntry has a similar property for custom data at the entry level. I updated my post. Thanks. — SwaroSh, Jul 21 '21 at 15:23
@Vrankela, I tried this out in code. It seems that CustomData is what's shown in the "Properties" tab. For both "Entry" and "Advanced" tabs, just entry.Strings.ReadSafe("") worked for me as long as the correct key names are used (and those entries exist in the database). I updated the answer. Hope this helps. — SwaroSh, Jul 26 '21 at 15:40

How do I read the custom string fields of an Entry in keepass?

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