Question

I’m attempting to do what is shown on the MonoTouch binding page and add some methods to a bound class. It says that all I have to do is include these in a partial class defined in a separate file that is included in the generation process with the -s option. The problem is that the generated class is not a partial class and when I run btouch I get the following errors:

$ /Developer/MonoTouch/usr/bin/btouch -v Node.cs -s:Extensions.cs
/Developer/MonoTouch/usr/bin/smcs -unsafe -target:library Node.cs -nowarn:436 -out:/var/folders/cy/g71b7mr91rn4slbpq5cm39140000gn/T/u983s550.k1k/temp.dll -r:/Developer/MonoTouch/usr/lib/btouch/btouch.exe Extensions.cs -r:/Developer/MonoTouch/usr/lib/mono/2.1/monotouch.dll
Node.cs(7,19): error CS0260: Missing partial modifier on declaration of type NodeNameSpace.Node'. Another partial declaration of this type exists
Extensions.cs(5,30): (Location of the symbol related to previous error)
Extensions.cs(5,30): error CS0261: Partial declarations ofNodeNameSpace.Node’ must be all classes, all structs or all interfaces
Node.cs(7,19): (Location of the symbol related to previous error)
Extensions.cs(7,29): error CS0106: The modifier public' is not valid for this item
Extensions.cs(10,25): error CS0531:NodeNameSpace.Node.IsExpanded.get’: interface members cannot have a definition
Extensions.cs(14,25): error CS0531: `NodeNameSpace.Node.IsExpanded.set’: interface members cannot have a definition
Compilation failed: 5 error(s), 0 warnings
btouch: API binding contains errors.

According to the MonoTouch page on binding:

Each class produced by the generator from the API definition file is a partial class

Node.cs

using System;
using MonoTouch.Foundation;

namespace NodeNameSpace
{
    [BaseType (typeof (NSObject))]
    interface Node
    {
        [Export ("expanded")]
        NSNumber Expanded { get; set; }
    }
}

Extensons.cs

using MonoTouch.Foundation;

namespace NodeNameSpace 
{
    public partial class Node
    {
        public bool IsExpanded
        {
            get
            {
                return Expanded.BoolValue;
            }
            set
            {
                Expanded = NSNumber.FromBool(value);
            }
        }
    }
}

Answer 1

It’s a long documentation page, but this should do what you want:

$ /Developer/MonoTouch/usr/bin/btouch Node.cs -x:Extensions.cs  
$ ls -l Node.dll 
-rwxr-xr-x  1 sebastienpouliot  staff  5120 30 Sep 13:30 Node.dll

Your issue was using -s which is used when compiling your interface to a partial class (too early for extensions methods) and to compile the bindings to a .dll.

What you wanted is -x where the source file would only be used for the second compilation (source to .dll). The -s option is most useful for enums since you’ll need them in both your interfaces and in the final assembly (.dll).

To get further help do:

/Developer/MonoTouch/usr/bin/btouch --help