调用原始方法时，Xamarin方法在设备上失败

Question

以下代码在模拟器中工作，但在调用_originalSetTextMethod(self, stringParam)时在设备上失败。

我怀疑这个问题与此有关，但无法确定C＃中的相应语法：https://developer.apple.com/library/archive/documentation/General/Conceptual/CocoaTouch64BitGuide/ConvertingYourAppto64-Bit/ConvertingYourAppto64-Bit.html#//apple_ref/doc/uid/TP40013501-CH3-SW22

任何人都可以提供关于如何让它在设备上运行的建议吗？谢谢。

public static class SetTextSwizzle
{
    [DllImport("/usr/lib/libobjc.dylib")]
    extern static IntPtr class_getInstanceMethod(IntPtr classHandle, IntPtr Selector);

    [DllImport("/usr/lib/libobjc.dylib")]
    extern static IntPtr imp_implementationWithBlock(ref BlockLiteral block);

    [DllImport("/usr/lib/libobjc.dylib")]
    extern static OriginalDelegate method_setImplementation(IntPtr method, IntPtr imp);

    static OriginalDelegate _originalSetTextMethod;

    [MonoNativeFunctionWrapper]
    public delegate void OriginalDelegate(IntPtr one, IntPtr two);
    delegate void CaptureDelegate(IntPtr block, IntPtr self, IntPtr paramOne);

    public static void Initialise() {
        OverrideSetText();
    }

    static void OverrideSetText()
    {
        var method = class_getInstanceMethod(new UILabel().ClassHandle, new Selector("setText:").Handle);
        var block_value = new BlockLiteral();
        CaptureDelegate d = SetTextAndFont;
        block_value.SetupBlock(d, null);
        var imp = imp_implementationWithBlock(ref block_value);
        _originalSetTextMethod = method_setImplementation(method, imp);
    }

    [MonoPInvokeCallback(typeof(CaptureDelegate))]
    static void SetTextAndFont(IntPtr block, IntPtr self, IntPtr stringParam)
    {
        var label = (UILabel)Runtime.GetNSObject(self);
        label?.SetFont();
        _originalSetTextMethod(self, stringParam);
    }
}

Answer 1

尝试将MonoNativeFunctionWrapper属性添加到CaptureDelegate。

[MonoNativeFunctionWrapper]委托void CaptureDelegate（IntPtr block，IntPtr self，IntPtr paramOne）;