There have been some fairly large code changes on moving from SharpDevelop 2.2 to 3.0 and addins written for 2.2 are unlikely to work without some modification. We will look at the changes in the core parts of SharpDevelop and then look at one way to do the porting.

Not all the differences are covered in the next section just those types and methods that are likely to have been used by an addin.

ICSharpCode.Core

NRefactory

ICSharpCode.SharpDevelop.Dom

    IClass type = callingClass.DeclaringType; 
    while (type != null) { 
      ... 
      type = type.DeclaringType; 
    } 

ICSharpCode.SharpDevelop.Widgets

ICSharpCode.SharpDevelop

void Deselected()
void Deselecting()
void Selected()
void SwitchedTo()

ICSharpCode.TextEditor

How to Port

This section looks at one way to port an addin. This is the way that the IronPython addin was ported from SharpDevelop 2.2 to SharpDevelop 3.

Download the source code for SharpDevelop 3.0 and 2.2.

Copy the source code of your addin to a folder inside SharpDevelop 3.0.

Run three copies of SharpDevelop, one to view SharpDevelop 2.2's source, one to view SharpDevelop 3.0's source, one with your addin. In the other copies of SharpDevelop you should open SharpDevelop.sln for 2.2 and 3.0. This will allow you to quickly search for SharpDevelop classes when you find your addin code will not compile.

Compile your code and fix the code or comment it out as you try to work out what is wrong.

You do not have to convert the project to use .NET 3.5. SharpDevelop itself uses it, but some of the addins do not. With the IronPython addin I needed to change it to use .NET 3.5 since there were some assembly conflicts between what SharpDevelop was using and what the addin was using. Obviously changing to use .NET 3.5 will allow you to use any new features of this framework.

.NET Framework Differences

One change in .NET 3.5 caused me a few problems when porting the IronPython addin. This was a change in MSBuild.

After finally getting the IronPython addin to compile with the modified SharpDevelop 3 assemblies there was an assembly conflict for MSBuild. The ICSharpCode.SharpDevelop assembly now uses MSBuild 3.5 assemblies whilst the IronPython build task project and test project were using MSBuild 2.0. This was fixed by converting these two projects so they use the .NET Framework 3.5. This can be done by opening the project's properties, selecting the Compiling tab, then clicking the Convert Project to C# 3.0 button. In the dialog that opens we select the "Change target framework to .NET 3.5" and click the OK button. After making this change the addin compiled and worked however all the unit tests for the IronPython build tasks were failing with the error:

System.ArrayTypeMismatchException : Attempted to access an element as a type incompatible with the array.

The test code that was failing:

PythonCompilerTask compiler = new PythonCompilerTask(); 
TaskItem sourceTaskItem = new TaskItem("test.py"); 
compiler.Sources = new ITaskItem[] {sourceTaskItem}; 

The last line was failing when the unit test was run. The TaskItem type implements the ITaskItem interface so the code should have worked. The reason for this error is that both the build task and build task tests project were referencing the MSBuild libraries just using the reference name.

    <Reference Include="Microsoft.Build.Framework" /> 
    <Reference Include="Microsoft.Build.Tasks" /> 
    <Reference Include="Microsoft.Build.Utilities" /> 

Running MSBuild from the command line the actual assemblies being used were a mix of 3.5 and 2.0 versions.

"Python.Build.Tasks.csproj": 
/reference:"C:\Program Files\Reference Assemblies\Microsoft\Framework\v3.5\Microsoft.Build.Framework.dll"  
/reference:C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Microsoft.Build.Tasks.dll  
/reference:C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Microsoft.Build.Utilities.dll  

Printing out the code base of the TaskItem and ITaskItem types whilst running the unit tests showed that the TaskItem was being taken from Microsoft.Build.Utilities assembly version 2.0 and the ITaskItem was being taken the Microsoft.Build.Framework 3.5 assembly. The TaskItem we actually needed was in the new Microsoft.Build.Utilities assembly version 3.5. Changing the project references so they used this new 3.5 assembly fixed the problem.