Identify the number of reference to a block

By Virupaksha Aithal

You can use BlockTableRecord:: GetBlockReferenceIds API  to get the object ids of the block references. You can get only direct reference (where the block is used directely, like in model space or inside another block) by passing true as first parameter.

[CommandMethod("BlockRefCount")]
static public void BlockRefCount()
{
 Document doc = Application.DocumentManager.MdiActiveDocument;
 Database db = doc.Database;
 Editor ed = doc.Editor;
 
 PromptStringOptions opts = 
    new PromptStringOptions("Enter block name");
    opts.AllowSpaces = true;
 
 PromptResult blockName = ed.GetString(opts);
 
 if (blockName.Status != PromptStatus.OK)
     return;
 
 using (Transaction tx =
                     db.TransactionManager.StartTransaction())
 {
     BlockTable blockTable = tx.GetObject(db.BlockTableId, 
                                OpenMode.ForRead) as BlockTable;
 
     if (blockTable.Has(blockName.StringResult))
     {
         BlockTableRecord block = tx.GetObject(
                               blockTable[blockName.StringResult],
                               OpenMode.ForRead) as BlockTableRecord;
         //only direct reference
         ObjectIdCollection ids = 
                            block.GetBlockReferenceIds(true, true);
 
         ed.WriteMessage("Number of reference is "
                                + ids.Count.ToString() + "n");
     }
     tx.Commit();
 }
}