使用Swig为C ++代码构建C#包装器时，是否可以将代码添加到现有方法中? [英] Is it possible to add code to an existing method when using Swig to build a C# wrapper for C++ code?

问题描述

使用Swig包装C ++代码时，可以将方法添加到使用％extend 的本机C ++类型.可以使用 将方法添加到C#包装器类％typemap(cscode).

When using Swig to wrap C++ code, it is possible to add methods to the native C++ type using %extend. It is possible to add methods to the C# wrapper class using %typemap(cscode).

包装类中已经存在一种方法，是否可以添加其他代码行?

Where a method already exists in the wrapper class, is there a way to add additional lines of code?

例如，我的C#包装器方法如下:

For example, my C# wrapper method looks like this:

  public void ItemChanged(CollectionObject collectionObject, string propertyName) {
    mynamespacePINVOKE.mynamespace_DataObjectCollection_ItemChanged(swigCPtr, CollectionObject.getCPtr(collectionObject), propertyName);
    if (mynamespacePINVOKE.SWIGPendingException.Pending) throw mynamespacePINVOKE.SWIGPendingException.Retrieve();
  }

我想添加一行代码:

  public void ItemChanged(CollectionObject collectionObject, string propertyName) {
    mynamespacePINVOKE.mynamespace_DataObjectCollection_ItemChanged(swigCPtr, CollectionObject.getCPtr(collectionObject), propertyName);
    if (mynamespacePINVOKE.SWIGPendingException.Pending) throw mynamespacePINVOKE.SWIGPendingException.Retrieve();
    **insert my line of code here**
  }

推荐答案

要编写自己的版本，您需要确保它不会与默认版本冲突.我认为最简单的方法是使用％csmethodmodifiers 和％rename 隐藏默认包装版本，从而使 ItemChanged 私有/受保护得到生成.一旦被隐藏.

In order to write your own version you're going to need to make sure it doesn't clash with the default one. I think the easiest way to do this would be to make ItemChanged private/protected using %csmethodmodifiers and %rename to hide the default wrapped version that gets generated. Once it's hidden.

然后，您可以使用cscode类型映射安全地编写自己的 ItemChanged 版本，该类型映射首先调用私有版本，然后根据需要调用其他代码.

You can then safely write your own version of ItemChanged using a cscode typemap that firstly calls the private version and then calls your additional code as you desire.

这是迄今为止解决问题的最干净的方法-您唯一可以将代码直接注入到生成的代码中的方法是作为参数/返回值编组的一部分-设置传入的参数，在处理或处理返回值后进行清理.弄乱其中一个类型图以注入一些代码会很混乱.

This is by far the cleanest way of solving the problem - the only way you're able to inject code directly into the generated code is as part of the argument/return value marshalling - setting up the arguments that get passed in, cleaning up after or handling the return value. Messing with one of those typemaps to inject some code would be fairly messy.

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