Changing block definition of an Block reference

Jul 5, 2012

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Below code shows the procedure to modify the block definition for block reference. Code, prompts the user to select a block reference and changes its definition so that block reference becomes reference for new block definition,

[CommandMethod("chageBlock")]
public static void chageBlock()
{
    Document doc = Application.DocumentManager.MdiActiveDocument;
    Database db = doc.Database;
    Editor ed = doc.Editor;
 
    PromptEntityOptions options =
        new PromptEntityOptions("nSelect block reference");
    options.SetRejectMessage("nSelect only block reference");
    options.AddAllowedClass(typeof(BlockReference), false);
 
    PromptEntityResult acSSPrompt = ed.GetEntity(options);
 
    if (acSSPrompt.Status != PromptStatus.OK)
        return;
 
    using (Transaction Tx = db.TransactionManager.StartTransaction())
    {
        //get the reference
        BlockReference blockRef = Tx.GetObject(acSSPrompt.ObjectId,
                               OpenMode.ForRead) as BlockReference;
 
        //block table record...
        BlockTable blockTable = Tx.GetObject(db.BlockTableId,
                                    OpenMode.ForRead) as BlockTable;
 
        //set the test as new block if present
        if (blockTable.Has("TEST"))
        {
            blockRef.UpgradeOpen();
 
            //set the id of the test block
            blockRef.BlockTableRecord = blockTable["TEST"];
        }
 
        Tx.Commit();
    }
}

Comments

7 responses to “Changing block definition of an Block reference”

Danny

July 6, 2012

I’m guessing this doesn’t work well on blocks with attributes. My biggest API wish is to make the process of inserting blocks with attributes as easy as just inserting a BlockReference and the attributes just insert as is. Subsequently having to add AttributeReferences and trying to match their properties is an itch that needs scratching.

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Gerrit van Diepen

June 10, 2013

Is it possible to check if an existing block, for example a block called ‘tree’ in the drawing needs updating from a drawing named ‘ c:\Blocks\tree.dwg’ This is because I have to check all the drawings created by a extern office who have to use our blocks without changing it.

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viru

June 10, 2013

Hi Gerrit,
No, at present it is not possible to check if the block need update from a source drawing file. You need to build your own logic to identify the block state.
regards
Viru

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Gerrit van Diepen

June 10, 2013

Hi Viru,
It is possible to add the “Tree.dwg” as a block called “test_tmp” without inserting it. But how can I check differences in the blocktablerecord between the blocks “tree” and “tree_tmp” ??
Thanks for the quick responce anyway …
Regards,
Gerrit

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viru

June 10, 2013

Hi,
Again, there is no API for this. You have to build your logic, like comparing entities in blocks, or counting the entities in blocks or using bounding boxes etc… No direct method.
Regards
Viru

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André Cristino

October 21, 2013

Good afternoon. I’m trying to use this code, but I found a case that it not work as well. When I try to change the definition from a new block that I have created in my test DWG, it disappear from the model. I wonder what is causing this problem?

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Wesley

July 25, 2016

I am trying to port some AutoLISP Code to .NET C Sharp for deleting the text objects from within block references. I am running into difficulty. Can you have a look and see if there is a more efficient way to do this and indeed a way that will work?
public class Class1 { [CommandMethod("DELTEXT")] public void DelText() { // Get the current document and database, and start a transaction Document acDoc = Application.DocumentManager.MdiActiveDocument; Database acCurDb = acDoc.Database; using (Transaction acTrans = acCurDb.TransactionManager.StartTransaction()) { // Open the Block table record for read BlockTable acBlkTbl; acBlkTbl = acTrans.GetObject(acCurDb.BlockTableId,OpenMode.ForRead) as BlockTable; // Open the Block table record Model space for read BlockTableRecord acBlkTblRec; acBlkTblRec = acTrans.GetObject(acBlkTbl[BlockTableRecord.ModelSpace],OpenMode.ForRead) as BlockTableRecord; int nCnt = 0; acDoc.Editor.WriteMessage("\nModel space objects: "); // Step through each object in Model space and display the Name of the Object foreach (ObjectId acObjId in acBlkTblRec) { //If the ObjectClass.DxFName is INSERT, then this block is a reference. if (acObjId.ObjectClass.DxfName == "INSERT") { //acDoc.Editor.WriteMessage("\n" + myBlk.Name); //acDoc.Editor.WriteMessage("\n" + myBlk.BlockName); //acDoc.Editor.WriteMessage("\n" + myBlk.ObjectId.ObjectClass.DxfName); //acDoc.Editor.WriteMessage("\n" + myBlk.ObjectId.ObjectClass.Name); //Open the Block Reference BlockReference myBlkReference = acTrans.GetObject(acObjId, OpenMode.ForRead) as BlockReference; BlockTableRecord xRefBlkTableRecs = acTrans.GetObject(myBlkReference.BlockTableRecord,OpenMode.ForRead) as BlockTableRecord; //For each Object in the Block Table Record of the Block Reference foreach (ObjectId myBlkObjId in xRefBlkTableRecs) { acDoc.Editor.WriteMessage("\n Object Class Name: " + myBlkObjId.ObjectClass.Name); acDoc.Editor.WriteMessage("\n Object Class DxFName: " + myBlkObjId.ObjectClass.DxfName); //Check if the object is a text object if (myBlkObjId.ObjectClass.DxfName.ToString().Equals("TEXT")) { acDoc.Editor.WriteMessage("\n This is a Text Item and Will be Deleted"); //This is certainly a text object - count it. nCnt = nCnt + 1; //Delete it myBlkReference.UpgradeOpen(); myBlkObjId.GetObject(OpenMode.ForWrite).Erase(); acTrans.Commit(); //acDoc.Editor.Regen(); } } } else { acDoc.Editor.WriteMessage("\n" + acObjId.ObjectClass.Name.ToString()); acDoc.Editor.WriteMessage("\n" + acObjId.ObjectClass.DxfName.ToString()); } //acTrans.Commit(); //acDoc.Editor.Regen(); } acDoc.Editor.WriteMessage("\n" + nCnt + "Text Objects in Document"); // If no objects are found then display a message if (nCnt == 0) { acDoc.Editor.WriteMessage("\n No Text objects found"); } } } }

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