read data from open drawing
Make a copy of the file in a temp location and read that db. You can delete the temp file when done. Here's an example:
// Read the source database
try
{
sourceDb.ReadDwgFile(sourceDwgName, FileShare.Read, true, "");
}
catch // read will fail if file is open in another instance so make a copy and read it.
{
string tempPath = Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments) + @"\Temp";
if (!Directory.Exists(tempPath))
Directory.CreateDirectory(tempPath);
string tempFileName = Path.GetFileName(sourceDwgName);
tempFilePath = tempPath + @"\" + tempFileName;
File.Copy(sourceDwgName, tempFilePath, true);
sourceDb.ReadDwgFile(tempFilePath, FileShare.Read, true, "");
deleteTempFile = true;
}
Try the code I added above. It may work faster than you expect. I don't know of another method but maybe someone else here does?
What error you encounter when the file is opened by another user? How do you know it is opened by another user (in AutoCAD)?
When you read the Dwg file into the Database, you used FlieShare.Read flag, it should be sufficient to read the data from the dwg file into Database, whether the drawing is opened in another AutoCAD session or not, unless the dwg file is opened by some application exclusively for writing, which is usually not the case when a drawing is opened in AutoCAD.
I strongly suspect that your issue is due to your code, and it very likely happens when you try to run the code repeatedly in the same AotuCAD session. This is because your code DOES not handle side Database correctly (see my comments beside your code):
Dim db As New DatabaseServices.Database //You created a new Database instance and only abandon it wihtout disposing
If tekening <> "basis" Then
db = New DatabaseServices.Database(False, True) //Hopefully you dispose this Database instance in code not showing here
Try
db.ReadDwgFile(tekening, System.IO.FileShare.Read, False, "")
Catch generatedExceptionName As System.Exception
myEd.WriteMessage(vbLf & "Unable to read drawing file.")
End Try
Else
db = New DatabaseServices.Database //You created a new Database and abandon it without disposing
db = myDWG.Database
End If
It is a common mistake for VB (classical VB or VB.NET) code that "New" keyword is abused in Dim ,,, As New... declaration. Also, in AutoCAD .NET API, if your code creates disposable object that is not to be persisted, your code is responsible to dispose it. If not, AutoCAD may become unstable.
In your code, if the variable takening is equal to "basis", your code ends up creating 2 database instances and only leave them inside AutoCAd running process without being disposed.
The code should be like this:
Dim db As Database //Notice that there is no "New" keyword, because this reference might be used to point to different Dataabase
If takening.ToLower()<>"basis" Then
Using db=New Database(False, Treu) ''the code create a new Database, wrapped inside Using...block, so it will be disposed when work is done
db.ReadDwgFile(.....,FileShere.Read,...)
DoSometingWithTransaction(db)
End Using
Else
db=myDwg.Database ''No need to wrap this Database in Using...block, because it is existing Database not created by your code
DoSomethingWithTransaction(db)
End If
Private Sub DoSomethingWithTransaction(db As Database)
Using tran As Transaction=db.TransactionManager.StartTransaction()
......
End Using
End Sub
The code structured in this way only create 1 instance of side database when it is needed and it get disposed as soon as the work is done. I'll bet it would work regardless the dwg file to be read is opened in other AutoCAD session or not.
Accepted solution
OK, since the file you try to open as side database is actually a Xref inside the current drawing, you actually have 2 ways to get information from it:
1. Open the drawing as side database. I wasn't completely correct in previous reply: the ReadDwgFile() failing if the drawing is opened in other AutoCAD session is because the second argument used in ReadDwgFile() method - FileShare.Read. This argument is only meant for subsequent file opening after this method successfully opens the file. But in the case of it being already opened by other AutoCAD session/user, you need to use another overloaded call:
ReadDwgFile (string, FileOpneMode, ...).
In my test, I have a drawing opened in another AutoCAD session. If I use FileShare.Read in ReadDwgFile(), I get file access exception. If I use FileOpenMode.OpenForReadAndAllShares, ReadDwgFile() succeeds.
2. To reach data inside Xrefed drawing, its Database is already in AutoCAD, you do not have to open it as side database.
Below is my test code. The scenario: in current open drawing there is an Xref, which has a few block references in modelspace. The Xrefed drawing in the meantime is opened in aother AutoCAD session. The code has 2 commands:
Command "UseSideDB" searches the current drawing for the file name of Xrefed file. Then open the found drawing file as side D.
Command "UseXrefDB" searches Xref and then search the Xref's DB.
Both commends result in the exactly same output.
using System.Collections.Generic;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Runtime;
using CadApp = Autodesk.AutoCAD.ApplicationServices.Application;
[assembly: CommandClass(typeof(ReadXrefDB.MyCommands))]
namespace ReadXrefDB
{
public class MyCommands
{
[CommandMethod("UseSideDB")]
public static void RunTest1()
{
var doc = CadApp.DocumentManager.MdiActiveDocument;
var ed = doc.Editor;
string blkNames = "";
var xrefFiles = GetXrefPaths(doc.Database);
if (xrefFiles.Length>0)
{
foreach (var xrefFile in xrefFiles)
{
if (System.IO.File.Exists(xrefFile))
{
string names = AccessDataInSideDatabase(xrefFile);
if (!string.IsNullOrEmpty(names))
{
blkNames = blkNames + "\n" + names;
}
}
}
}
PrintResult(ed, blkNames);
}
[CommandMethod("UseXrefDB")]
public static void RunTest2()
{
var doc = CadApp.DocumentManager.MdiActiveDocument;
var ed = doc.Editor;
string blkNames = "";
XrefGraph graph = doc.Database.GetHostDwgXrefGraph(false);
for (int i = 0; i < graph.NumNodes; i++)
{
var node = graph.GetXrefNode(i);
if (node.Database != null)
{
if (node.Database.Filename.ToLower() != doc.Database.Filename.ToLower())
{
string names = SearchDBForBlockReferences(node.Database);
if (!string.IsNullOrEmpty(names))
{
blkNames = blkNames + "\n" + names;
}
}
}
}
PrintResult(ed, blkNames);
}
private static string[] GetXrefPaths(Database db)
{
var paths = new List<string>();
XrefGraph graph = db.GetHostDwgXrefGraph(false);
for (int i=0; i<graph.NumNodes; i++)
{
var node = graph.GetXrefNode(i);
if (node.Database!=null)
{
if (node.Database.Filename.ToLower() != db.Filename.ToLower())
{
paths.Add(node.Database.Filename);
}
}
}
return paths.ToArray();
}
private static string AccessDataInSideDatabase(string fileName)
{
string names = null;
using (var db = new Database(false, true))
{
db.ReadDwgFile(fileName,FileOpenMode.OpenForReadAndAllShare, false, null);
names= SearchDBForBlockReferences(db);
}
return names;
}
private static string SearchDBForBlockReferences(Database db)
{
var blkNames = new List<string>();
using (var tran = db.TransactionManager.StartTransaction())
{
var model = (BlockTableRecord)tran.GetObject(
SymbolUtilityServices.GetBlockModelSpaceId(db), OpenMode.ForRead);
foreach (var id in model)
{
if (id.ObjectClass.DxfName.ToLower()=="insert")
{
var bref = (BlockReference)tran.GetObject(id, OpenMode.ForRead);
string name;
if (bref.Name.IndexOf("|") > 0)
name = bref.Name.Split('|')[1]; //Block name is in format of "[Xref Name]|[Block Name]"
else
name = bref.Name;
blkNames.Add(name);
}
}
tran.Commit();
}
return string.Join("\n", blkNames.ToArray());
}
private static void PrintResult(Editor ed, string result)
{
if (!string.IsNullOrEmpty(result))
ed.WriteMessage("\nBlocks found in Xrefed drawing: {0}", result);
else
ed.WriteMessage("\nNo block reference found in Xrefed drawing.");
Autodesk.AutoCAD.Internal.Utils.PostCommandPrompt();
}
}
}
HTH