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Database.md

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Database Class

Overview

The Database class represents an AutoCAD drawing database. It is the central repository for all graphical and non-graphical objects in a drawing, including entities, symbol tables, and dictionaries.

Namespace

Autodesk.AutoCAD.DatabaseServices

Inheritance Hierarchy

System.Object
  └─ RXObject
      └─ DBObject
          └─ Database

Key Properties

Symbol Table Properties

Property Type Description
BlockTableId ObjectId Gets the ObjectId of the BlockTable
LayerTableId ObjectId Gets the ObjectId of the LayerTable
LinetypeTableId ObjectId Gets the ObjectId of the LinetypeTable
TextStyleTableId ObjectId Gets the ObjectId of the TextStyleTable
DimStyleTableId ObjectId Gets the ObjectId of the DimStyleTable
UcsTableId ObjectId Gets the ObjectId of the UcsTable
ViewTableId ObjectId Gets the ObjectId of the ViewTable
ViewportTableId ObjectId Gets the ObjectId of the ViewportTable
RegAppTableId ObjectId Gets the ObjectId of the RegAppTable

Dictionary Properties

Property Type Description
NamedObjectsDictionaryId ObjectId Gets the Named Objects Dictionary (NOD)
GroupDictionaryId ObjectId Gets the Group Dictionary
MLStyleDictionaryId ObjectId Gets the Multiline Style Dictionary
LayoutDictionaryId ObjectId Gets the Layout Dictionary
PlotSettingsDictionaryId ObjectId Gets the Plot Settings Dictionary
ColorDictionaryId ObjectId Gets the Color Dictionary
MaterialDictionaryId ObjectId Gets the Material Dictionary
VisualStyleDictionaryId ObjectId Gets the Visual Style Dictionary

Current State Properties

Property Type Description
CurrentSpaceId ObjectId Gets the ObjectId of the current space (Model or Paper)
Clayer ObjectId Gets/sets the current layer
Celtype ObjectId Gets/sets the current linetype
Dimstyle ObjectId Gets/sets the current dimension style
Textstyle ObjectId Gets/sets the current text style
Cmaterial ObjectId Gets/sets the current material

Drawing Properties

Property Type Description
TileMode bool Gets/sets whether TileMode is active (Model Space)
Filename string Gets the full path of the drawing file
OriginalFileName string Gets the original filename before any saves
DwgVersion DwgVersion Gets the DWG file version
LastSavedAsVersion DwgVersion Gets the version last saved as

System Properties

Property Type Description
TransactionManager TransactionManager Gets the transaction manager for this database
ObjectContextManager ObjectContextManager Gets the object context manager
Dimscale double Gets/sets the dimension scale
Ltscale double Gets/sets the linetype scale

Key Methods

Method Return Type Description
ReadDwgFile(string, FileOpenMode, bool, string) Database Reads a DWG file into a new Database object
SaveAs(string, DwgVersion) void Saves the database to a file
Audit(bool, bool) void Audits the database for errors
Purge(ObjectIdCollection) void Purges unused objects
GetObjectId(bool, Handle, int) ObjectId Gets an ObjectId from a handle
GetAcadDatabase() IntPtr Gets a pointer to the underlying AcDbDatabase

Code Examples

Example 1: Accessing Symbol Tables

Document doc = Application.DocumentManager.MdiActiveDocument;
Database db = doc.Database;

using (Transaction tr = db.TransactionManager.StartTransaction())
{
    // Access BlockTable
    BlockTable bt = tr.GetObject(db.BlockTableId, OpenMode.ForRead) as BlockTable;
    
    // Access LayerTable
    LayerTable lt = tr.GetObject(db.LayerTableId, OpenMode.ForRead) as LayerTable;
    
    // Access current space
    BlockTableRecord btr = tr.GetObject(db.CurrentSpaceId, OpenMode.ForRead) as BlockTableRecord;
    
    tr.Commit();
}

Example 2: Reading an External DWG File

using (Database extDb = new Database(false, true))
{
    extDb.ReadDwgFile("C:\\Drawings\\Sample.dwg", FileOpenMode.OpenForReadAndAllShare, true, "");
    
    using (Transaction tr = extDb.TransactionManager.StartTransaction())
    {
        BlockTable bt = tr.GetObject(extDb.BlockTableId, OpenMode.ForRead) as BlockTable;
        // Work with external database
        
        tr.Commit();
    }
}

Example 3: Getting Current Layer

Database db = Application.DocumentManager.MdiActiveDocument.Database;

using (Transaction tr = db.TransactionManager.StartTransaction())
{
    LayerTableRecord currentLayer = tr.GetObject(db.Clayer, OpenMode.ForRead) as LayerTableRecord;
    
    Editor ed = Application.DocumentManager.MdiActiveDocument.Editor;
    ed.WriteMessage($"\nCurrent layer: {currentLayer.Name}");
    
    tr.Commit();
}

Example 4: Purging Unused Objects

Database db = Application.DocumentManager.MdiActiveDocument.Database;

using (Transaction tr = db.TransactionManager.StartTransaction())
{
    ObjectIdCollection idsToPurge = new ObjectIdCollection();
    
    // Get purgeable objects
    db.Purge(idsToPurge);
    
    if (idsToPurge.Count > 0)
    {
        // Purge the objects
        foreach (ObjectId id in idsToPurge)
        {
            DBObject obj = tr.GetObject(id, OpenMode.ForWrite);
            obj.Erase();
        }
    }
    
    tr.Commit();
}

Related Objects

Example 5: Accessing Named Objects Dictionary

using (Transaction tr = db.TransactionManager.StartTransaction())
{
    // Get the Named Objects Dictionary (NOD)
    DBDictionary nod = tr.GetObject(db.NamedObjectsDictionaryId, OpenMode.ForRead) as DBDictionary;
    
    ed.WriteMessage("\nNamed Objects Dictionary entries:");
    foreach (DBDictionaryEntry entry in nod)
    {
        ed.WriteMessage($"\n  {entry.Key}");
    }
    
    tr.Commit();
}

Example 6: Accessing Group Dictionary

using (Transaction tr = db.TransactionManager.StartTransaction())
{
    DBDictionary groupDict = tr.GetObject(db.GroupDictionaryId, OpenMode.ForRead) as DBDictionary;
    
    ed.WriteMessage($"\nNumber of groups: {groupDict.Count}");
    
    foreach (DBDictionaryEntry entry in groupDict)
    {
        Group group = tr.GetObject(entry.Value, OpenMode.ForRead) as Group;
        ed.WriteMessage($"\n  Group: {entry.Key} - {group.Count} objects");
    }
    
    tr.Commit();
}

Example 7: Accessing Layout Dictionary

using (Transaction tr = db.TransactionManager.StartTransaction())
{
    DBDictionary layoutDict = tr.GetObject(db.LayoutDictionaryId, OpenMode.ForRead) as DBDictionary;
    
    ed.WriteMessage("\nLayouts in drawing:");
    foreach (DBDictionaryEntry entry in layoutDict)
    {
        Layout layout = tr.GetObject(entry.Value, OpenMode.ForRead) as Layout;
        ed.WriteMessage($"\n  {layout.LayoutName}");
    }
    
    tr.Commit();
}

Example 8: Creating Entry in Named Objects Dictionary

using (Transaction tr = db.TransactionManager.StartTransaction())
{
    DBDictionary nod = tr.GetObject(db.NamedObjectsDictionaryId, OpenMode.ForWrite) as DBDictionary;
    
    // Create a custom dictionary
    string dictName = "MyCustomDictionary";
    
    if (!nod.Contains(dictName))
    {
        DBDictionary customDict = new DBDictionary();
        nod.SetAt(dictName, customDict);
        tr.AddNewlyCreatedDBObject(customDict, true);
        
        ed.WriteMessage($"\nCreated custom dictionary: {dictName}");
    }
    
    tr.Commit();
}

Working with TileMode (Model/Paper Space)

Database db = Application.DocumentManager.MdiActiveDocument.Database;

if (db.TileMode)
{
    // Currently in Model Space
}
else
{
    // Currently in Paper Space
}

Accessing Model Space and Paper Space

using (Transaction tr = db.TransactionManager.StartTransaction())
{
    BlockTable bt = tr.GetObject(db.BlockTableId, OpenMode.ForRead) as BlockTable;
    
    // Model Space
    BlockTableRecord modelSpace = tr.GetObject(bt[BlockTableRecord.ModelSpace], 
        OpenMode.ForRead) as BlockTableRecord;
    
    // Paper Space
    BlockTableRecord paperSpace = tr.GetObject(bt[BlockTableRecord.PaperSpace], 
        OpenMode.ForRead) as BlockTableRecord;
    
    tr.Commit();
}

References