扩展ImageMagickNet

Question

我试图向ImageMagickNet类添加一个自定义函数。它应该使用ImageMagick.NET项目中的IsSimilarImage magick方法，但我对是否必须通过Magick++路由此方法感到困惑，因为在.NET端可用的任何功能都起源于Magick++。

- Becky Green

Answer 1

这篇文章有些老，但因为没有得到回答，所以我来回答一下。

请注意，我没有查看ImageMagick库，所以下面代码中的任何实现细节都仅是一个示例。请用正确的实现替换垃圾代码。假设它正在导出有效的.NET对象，那么它将按照以下方式工作：

' Put your extension methods or properties in a clearly labeled module file, on its own within your project
Module ImageMagickNetExtensions

    ' Define an extension method by using the ExtensionAttribute, and make the first argument
    ' for the method the type that you wish to extend. This will serve as a reference to the extended
    ' instance, so that you can reference other methods and properties within your extension code.
    <Extension()> _
    Public Function SomeExtensionFunction(ByVal imn As ImageMagickNet, ByVal filename As String) As Boolean
        Return imn.IsSimilarImage(filename)
    End Function

End Module

Class SomeClass
    ' To use your extension method within your project containing the extension module, simply
    ' call it on any valid instance of the type you have extended. The compiler will call your code
    ' whenever it sees reference to it, passing a reference to your extended instance.
    Private imn As New ImageMagickNet

    Private Sub DoSomething()
        If imn.SomeExtensionFunction("c:\someimage.jpg") Then
            ...
        End If
    End Sub
End Class

- Drunken Code Monkey