---
source_files:
  - DataPRO/Modules/PreviousDBVersions/Version57/DatabaseExport/Users/IUIItems.cs
  - DataPRO/Modules/PreviousDBVersions/Version57/DatabaseExport/Users/ITagAware.cs
  - DataPRO/Modules/PreviousDBVersions/Version57/DatabaseExport/Users/Tags.cs
  - DataPRO/Modules/PreviousDBVersions/Version57/DatabaseExport/Users/User.cs
generated_at: "2026-04-17T15:54:08.207380+00:00"
model: "zai-org/GLM-5-FP8"
schema_version: 1
sha256: "3cdbf9b023e772e8"
---

# Documentation: DatabaseExport Users Module (Version 57)

## 1. Purpose

This module provides the user management subsystem for the `DatabaseExport` namespace, handling user identity, roles, permissions, visibility settings, and tag associations. It implements a tag caching system for efficient tag lookups, supports serialization of user data for XML storage, and manages per-user permissions on UI items. The module is part of a legacy database version (Version 57) and contains abstractions for database-backed user entities with timestamp and tagging capabilities.

---

## 2. Public Interface

### `IUIItems` (Interface)
**File:** `IUIItems.cs`
```csharp
string GetName();
```
- Returns the name of a UI item. Implementers provide a string identifier used for permission and visibility lookups in the `User` class.

---

### `TagAwareBase` (Abstract Class)
**File:** `ITagAware.cs`
**Inherits from:** `DbTimeStampBase`

**Properties:**
```csharp
byte[] TagsBlobBytes { get; set; }
int[] TagIDs { get; set; }
```
- `TagsBlobBytes`: Converts `TagIDs` to/from a byte array (4 bytes per int). The setter silently catches exceptions during conversion.
- `TagIDs`: Backed by `_tagIDs`, defaults to empty array. Setter null-coalesces to empty array.

**Methods:**
```csharp
string GetTagsCommaSeperatedString();
virtual string[] GetTagsArray();
```
- `GetTagsCommaSeperatedString()`: Returns comma-separated string of tag text by delegating to `GetTagsArray()`.
- `GetTagsArray()`: Returns string array of tag text by calling `Tags.GetTagTextFromIDs(TagIDs)`.

---

### `Tags` (Class)
**File:** `Tags.cs`

**Nested Class `Tag`:**
```csharp
public const int INVALID_ID = -1;
int ID { get; set; }
string Text { get; set; }
bool IsObsolete { get; set; }
```
- Implements `ICloneable`. Constructor from `DataRow` reads fields via `DbOperations.Tags.TagFields` enum. Copy constructor available.

**Static Properties:**
```csharp
static Tags TagsInstance { get; }
```
- Singleton accessor, lazily instantiated.

**Static Methods:**
```csharp
static string GetTagTextFromID(int tagID);
static string[] GetTagTextFromIDs(int[] tagID);
```
- `GetTagTextFromID(int)`: Returns tag text for a valid ID (> 0 and not `Tag.INVALID_ID`), or `null` if invalid/not found.
- `GetTagTextFromIDs(int[])`: Returns array of tag texts, skipping invalid IDs and null/whitespace results.

**Constructor:**
```csharp
Tags(); // Initializes _tagsLookup and calls UpdateList()
```

---

### `User` (Class)
**File:** `User.cs`
**Inherits from:** `TagAwareBase`

**Nested Enums:**
```csharp
public enum DefaultRoles { Administrator = 0, PowerUser = 1, User = 2, Guest = 3 }
public enum UserPermissionLevels { Deny = 0, Read = 1, ReadAndExecute = 2, Edit = 3, Admin = 4 }
public enum Tags { User, Role, Version, LastModified, LastModifiedBy, Name, UserName, Password, LocalOnly, Permissions, Visibility, Id }
public enum XmlFields { ID, UserName, DisplayName, Password, IUIItemPermissions, IUIItemVisibility, Role, LastModified, LastModifiedBy, Version, LocalOnly, UserTags }
```

**Constants:**
```csharp
private const string DEFAULT_LAST_MODIFIED_BY = "---";
private const string DEFAULT_ADMIN_USERNAME = "Admin";
private const string DEFAULT_GUEST_USERNAME = "Guest";
private const string DEFAULT_POWERUSER_USERNAME = "PowerUser";
private const string DEFAULT_USER_USERNAME = "User";
private const int INVALID_ID = -1;
```

**Properties:**
```csharp
bool IsADefaultUser { get; }
string Name { get; set; }
string UserName { get; set; }
int Id { get; set; }
DefaultRoles Role { get; set; }
int Version { get; set; }
DateTime LastModified { get; set; }
string LastModifiedBy { get; set; }
bool LocalOnly { get; set; }
```
- `Role` setter throws `NotSupportedException` if user is a default user and role changes.
- All setters use `SetProperty(ref field, value, Tags.EnumName.ToString())`.

**Constructor:**
```csharp
User(DataRow row);
```
- Populates user from `DbOperations.Users.UserFields` columns.

**Methods:**
```csharp
override ConstraintHelper[] GetConstraints();
override string LookupTable { get; }
string GetPermissionSerialized();
static string GetDefaultUserName(DefaultRoles role);
string GetVisibilitySerialized();
Dictionary<string, string> GetValues();
```
- `GetConstraints()`: Returns single constraint on `UserName` column.
- `LookupTable`: Returns `DbOperations.Users.USERS_TABLE`.
- `GetPermissionSerialized()`: Returns `"ItemName=PermissionValue,..."` string from `_tabPermissions` dictionary.
- `GetDefaultUserName(DefaultRoles)`: Maps role enum to default username string; throws `NotSupportedException` for unknown roles.
- `Get