Latest Contributions by AlexanderGray

This is a very interesting thread, I am not sure what esri's position is on the whole thing.  I guess it depends what kind of development you are doing.  If you are doing windows forms in .NET then I think engine is the tool.  If you want to do a WPF project then the Runtime is probably better suited (someone can chime in now).  That opens up the debate to windows forms vs WPF.  There has been a lot said about it by more knowledgeable people than me, so you can google that. ... View more

1&2 Your components already have a GUID in the COM section.  You are meant to give a unique but readable (by the developer) name.  I usually put ProjectName_ClassName.  Keep them unique though so avoid reusing the names from your VB6 projects.  The category, caption, tool tip, etc. usually goes in the project resource file. 3.  In your commands, you can override the Enabled property.  Get a reference to your extension in the command, check the state of the extension and return false if the extension is not enabled.  Make sure you keep the reference to the extension to avoid constantly looking it up. ... View more

This goes for developers too.  Making a useful icon in a 32X32 image is almost impossible.  This is so limitting! ... View more

The code assumes that nulls are to be treated the same as zero in all cases.  That is a decision you have to make to start with.  In my work, there are cases where that assumption is incorrect so that is something to think about.  You may also return Double.NaN but then you still have to check it before using it. Putting a not null constraint on the field with a default value of zero would avoid this problem to start with if you have that sort of control over the database. ... View more

ToString will fail if the object is dbnull value.  Happens all the time, you have to check for that every time, it is a real pain.  If the type returned was a AO type, I would write an extension to check for that but I hesitate on writing extensions for type object. ... View more

I have never done this but my understanding is that the TOC inherits from a C++ treeview.  I know people who, in C++, were able to downcast the TOC to the C++ treeview type and read the properties of the treeview to access properties not exposed in AO.  You could probably change the properties too. Not too sure if this would be of any use though or if it is really supportable. ... View more

If the value in the field is null, you will not be able to cast it to double.  When there is a null value in a field, .net returns a dbnull.value which cannot be cast to a double even if the field type is double.  Perhaps this is the problem. ... View more

You can't clone the map itself.  The only way I see this working, is looping through all the elements in one map and cloning them and adding them to the other map.  However a map is a lot more than layers and a graphicscontainer.  There are many properties that would need cloning.  You could also create a stream and use the map's Ipersiststream to save the map to the stream and then load it back into a different map object. ... View more

Commands, tools and extensions can work with different applications, ArcMap, ArcCatalog, Engine etc.  You get to choose which one on creation or make it generic across applications, I think you got that part.  For just In Time extensions, the "on create" doesn't happen when ArcMap starts up, only when it is needed.  This makes ArcMap start up faster but you have to be mindful of when your extension gets initialized.  The second option is what application (so ArcMap) and configurable.  Configurable extensions get placed in the ArcMap/tools/extension menu and you can turn it on and off like other ESRI extensions like Spatial analyst.  Blank extension don't have that option and are assumed always on.  So for configurable extension, IExtensionConfig gets implemented and stubbed out.  That is where the code that happens when you turn the extension on and off is.  IPersistVariant is needed to save data with the extension. BaseToolbar has very few options, basically just the applications it is registered with, Same for basecommand except there are more types of commands based on the types of application they are supposed to interact with. Regardless of which type you choose, you can changed it in the com registration functions but choosing the right one makes all that stuff happen. So... Step 1 is identify the type or types of applications you need to do.  Making a command to work in ArcMap and Engine and Globe is all well and good but extra care needs to be taken to interact only with interfaces common to all of them.  If you don't need to, don't do it. As far as using JIT extensions, unless performance is a major consideration or if you extension takes a really long time to start (maybe retrieving data from a database or network) and it is not used often, I say don't bother.  Generally if you build your own extension, its' because the users want to use it all the time, so the performance hit to start the extension will happen anyway, differing it won't gain much.  For ESRI extensions it made a lot of sense because users weren't always using 3D analyst, for example, every session.  Also if start-up times are a big deal, you might want to put some time metrics in to figure out if the JIT really makes a difference. ... View more

I think the last time there was a book on ArcObjects was 8.something.  I don't see another book on AO coming out any time.  I used to hate those books, spending countless hours doing keyword searches on the pdf.  The help has a lot in it but I had to get used to how it was organized.  Mostly I learned by looking at examples and trying things myself.  The following has a bunch of info on extensions: http://help.arcgis.com/en/sdk/10.0/arcobjects_net/conceptualhelp/index.html#/Creating_an_application_extension/00010000001v000000/ ... View more

For files added to a map or a map control, AO keeps a lock on them even when they are removed from the map or map control.  You can try using disconnect or even call the com release on the raster but I have had more luck using IDataset.Delete and IDataset.CanDelete in those cases rather that calls to system.io.file.delete. ... View more

I use VS2008 but I put the AO license and product initialization in the ClassInitialize method of the test class with the appropriate method decorator.  I have never done it in the Assembly initialize method. ... View more

Delphi is not a platform officially supported by ESRI.  I don't know of anyone using it with ArcObjects, I suspect that is the case for a lot of people on the forum. ... View more