Generating preview icons for programmatically created blocks

By Virupaksha Aithal

Below code shows the procedure to generate the preview icons for programmatically created blocks. Code uses AutoCAD built in command “BLOCKICON” to create the icon.

[CommandMethod("BlkPreview", CommandFlags.Session)]
static public void BlkPreview()
{
    Document doc =
        Application.DocumentManager.MdiActiveDocument;
    Database db = doc.Database;
 
    using (Transaction Tx =
        db.TransactionManager.StartTransaction())
    {
        BlockTable table =
            Tx.GetObject(db.BlockTableId, 
                OpenMode.ForRead) as BlockTable;
 
        //"Test" - block whose preview icon need to Generate.
        BlockTableRecord blk =
            Tx.GetObject(table["Test"], 
                    OpenMode.ForRead) as BlockTableRecord;
 
        object app = Application.AcadApplication;
 
        object ActiveDocument =
        app.GetType().InvokeMember(
          "ActiveDocument", BindingFlags.GetProperty,
         null, app, null
       );
 
        object[] dataArry = new object[1];
        dataArry[0] = "_.BLOCKICON " + blk.Name + "n";
        ActiveDocument.GetType().InvokeMember("SendCommand",
            System.Reflection.BindingFlags.InvokeMethod,
            null, ActiveDocument, dataArry);
 
        Tx.Commit();
    }
}