Here is quick sample how to do it,
see if that helps
[CommandMethod("chatts")]
public void SelectByAttributes()
{
ObjectIdCollection blkcoll = new ObjectIdCollection();
//block name
string blkname = "MyBlock";//<-- change the block name here
// tag name to search for
string atag = "BLOCK_NAME";//<-- change the attribute tag here, case-sensitive for selection filter!
//new attribute value
string newval = "Foo";//<-- change the new attribute value here
// get active drawing
Document doc = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument;
// get document editor
Editor ed = doc.Editor;
//get document database
Database db = doc.Database;
// build selection filter
// to select all attributed blocks by its name in the Model space:
SelectionFilter sfilter = new SelectionFilter(new TypedValue[]
{
new TypedValue (-4,"<AND"),
new TypedValue(410, "Model"),
new TypedValue((int)DxfCode.BlockName,blkname),
new TypedValue((int)DxfCode.HasSubentities,1),
new TypedValue (-4,"AND>")
});
// request for blocks to be selected all in the model space
PromptSelectionResult res = ed.SelectAll(sfilter);
try
{
//check on valid selection result
if (res.Status == PromptStatus.OK)
{
//display result
ed.WriteMessage("\n---> Selected {0} objects", res.Value.Count);// debug only, maybe removed
//get object transaction
using (Transaction tr = doc.TransactionManager.StartTransaction())
{
ObjectId[] ids = res.Value.GetObjectIds();
//iterate through the selection set
foreach (ObjectId id in ids)
{
if (id.IsValid && !id.IsErased)
{
Entity ent = tr.GetObject(id, OpenMode.ForRead, false) as Entity;
ed.WriteMessage("\n---> {0}", ent.GetRXClass().DxfName);// debug only, maybe removed
//cast entity as BlockReference
BlockReference bref = ent as BlockReference;
if (bref != null)
{
foreach (ObjectId aid in bref.AttributeCollection)
{
Entity subent = tr.GetObject(aid, OpenMode.ForRead, false) as Entity;
if (subent.GetType() == typeof(AttributeReference))
{
//cast entity as AttributeReference
AttributeReference atref = subent as AttributeReference;
if (atref != null)
{
// check on desired tag name
if (atref.Tag == atag)
{
atref.UpgradeOpen();
atref.TextString = newval;
atref.DowngradeOpen();
}
}
}
}
}
}
}
tr.Commit();
}
}
}
catch (System.Exception ex)
{
ed.WriteMessage(ex.Message);
}
} And here is the same on VB.Net:
<CommandMethod("chatts")> _
Public Sub SelectByAttributes()
Dim blkcoll As New ObjectIdCollection()
'block name
Dim blkname As String = "MyBlock" '<-- change the block name here
' tag name to search for
Dim atag As String = "TAG1" '<-- change the attribute tag here
'new attribute value
Dim newval As String = "Value1" '<-- change the new attribute value here
' get active drawing
Dim doc As Document = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument
' get document editor
Dim ed As Editor = doc.Editor
'get document database
Dim db As Database = doc.Database
' build selection filter
' to select all attributed blocks by its name in the Model space:
Dim sfilter As New SelectionFilter(New TypedValue() {New TypedValue(-4, "<AND"), New TypedValue(410, "Model"), New TypedValue(CInt(DxfCode.BlockName), blkname), New TypedValue(CInt(DxfCode.HasSubentities), 1), New TypedValue(-4, "AND>")})
' request for blocks to be selected all in the model space
Dim res As PromptSelectionResult = ed.SelectAll(sfilter)
Try
'check on valid selection result
If res.Status = PromptStatus.OK Then
'display result
ed.WriteMessage(vbLf & "---> Selected {0} objects", res.Value.Count)' debug only, maybe removed
'get object transaction
Using tr As Transaction = doc.TransactionManager.StartTransaction()
Dim ids As ObjectId() = res.Value.GetObjectIds()
'iterate through the selection set
For Each id As ObjectId In ids
If id.IsValid AndAlso Not id.IsErased Then
Dim ent As Entity = TryCast(tr.GetObject(id, OpenMode.ForRead, False), Entity)
ed.WriteMessage(vbLf & "---> {0}", ent.GetRXClass().DxfName) ' debug only, maybe removed
'cast entity as BlockReference
Dim bref As BlockReference = TryCast(ent, BlockReference)
If bref IsNot Nothing Then
For Each aid As ObjectId In bref.AttributeCollection
Dim subent As Entity = TryCast(tr.GetObject(aid, OpenMode.ForRead, False), Entity)
If TypeOf subent Is AttributeReference Then
'cast entity as AttributeReference
Dim atref As AttributeReference = TryCast(subent, AttributeReference)
If atref IsNot Nothing Then
' check on desired tag name
If atref.Tag = atag Then
atref.UpgradeOpen()
atref.TextString = newval
atref.DowngradeOpen()
End If
End If
End If
Next
End If
End If
Next
tr.Commit()
End Using
End If
Catch ex As System.Exception
ed.WriteMessage(ex.Message)
End Try
End Sub
~'J'~
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