Question

我正在使用Adobe Acrobat SDK，并且尝试通过将InvokeMember调用包装在Extension方法中以使代码更易读来清理COM调用。

我要编写的扩展方法如下：

using System;
using System.Reflection;

public static class Invoke_Extension
{
    public static object CallJSfunction(this Object adobeComObject, string sJSfunction, params object[] oPlist)
    {

        Type T = adobeComObject.GetType();

        return T.InvokeMember(
                        sJSfunction,
                        BindingFlags.GetProperty | //fixed per Simon's comment
                        BindingFlags.Public |
                        BindingFlags.Instance,
                        null, adobeComObject, oPlist);
    }
}

它将替换Adobe示例代码中的COM调用，如下所示：

    // Example from the Adobe SDK sample code
using System;
using System.Reflection;
using Acrobat;
//---------------- Create necessary objects ----------------------
    AcroAVDoc g_AVDoc = new AcroAVDoc();
    g_AVDoc.Open(filename, "");
    CAcroPDDoc pdDoc = (CAcroPDDoc)g_AVDoc.GetPDDoc();
    //Acquire the Acrobat JavaScript Object interface from the PDDoc object
    Object jsObj = pdDoc.GetJSObject();

//------- This is the part I am trying to make more readable --------
    Type T = jsObj.GetType();

    // total number of pages
    double nPages = (double)T.InvokeMember(
                "numPages",
                BindingFlags.GetProperty |
                BindingFlags.Public |
                BindingFlags.Instance,
                null, jsObj, null);

//-------------------------------------------------------------------------
//-- using the extension method, the two calls above are replaced with: ---

    double nPages2 = (double)jsObj.CallJSfunction("numPages", null);
/--------------------------------------------------------------------------
// ...but the InvokeMember call within the extension method is throwing an error.




//BTW, the optional parameters in the Extension method is because some of the functions have more than one parameter eg.
    object[] addTextWatermarkParam = { currentTime.ToShortTimeString(), 1, "Helvetica", 100, blueColorObj, 0, 0, true, true, true, 0, 3, 20, -45, false, 1.0, false, 0, 0.7 };
    T.InvokeMember(
            "addWatermarkFromText",
            BindingFlags.InvokeMethod |
            BindingFlags.Public |
            BindingFlags.Instance,
            null, jsObj, addTextWatermarkParam);
// which would be replaced with
    jsObj.CallJSfunction("addWatermarkFromText",currentTime.ToShortTimeString(), 1, "Helvetica", 100, blueColorObj, 0, 0, true, true, true, 0, 3, 20, -45, false, 1.0, false, 0, 0.7 );

完整的错误为：

System.Reflection.TargetInvocationException HResult = 0x80131604 调用目标已抛出Message = Exception。来源= mscorlib 堆栈跟踪：在System.RuntimeType.InvokeDispMethod上（字符串名称，BindingFlags invokeAttr，对象目标，Object [] args，Boolean [] byrefModifiers，Int32文化，String [] namedParameters）在System.RuntimeType.InvokeMember处（字符串名称，BindingFlags bindingFlags，活页夹绑定程序，对象目标，Object []提供的Args，ParameterModifier []修饰符，CultureInfo文化，String [] namedParams）在System.Type.InvokeMember处（字符串名称，BindingFlags invokeAttr，活页夹装订器，对象目标，Object [] args）在Z :: mike \ Downloads \ Adobe \ Acrobat DC SDK \ Version 1 \ InterAppCommunicationSupport \ C＃Samples \ JSObjectControlCS \ JSObjectControlCS \ Invoke_Extension.cs：第11行中的Invoke_Extension.CallJSfunction（Object adobeComObject，String sJSfunction，Object [] oPlist）中在Z：\ mike \ Downloads \ Adobe \ Acrobat DC SDK \ Version 1 \ InterAppCommunicationSupport \ C＃Samples \ JSObjectControlCS \ JSObjectControlCS \ Form1.cs：line 239中的JSObjectControlCS.JSObjectControlForm.searchButton_Click（Object sender，EventArgs e）在System.Windows.Forms.Control.OnClick（EventArgs e）在System.Windows.Forms.Button.OnClick（EventArgs e）在System.Windows.Forms.Button.OnMouseUp（MouseEventArgs mevent）在System.Windows.Forms.Control.WmMouseUp上（消息和m，MouseButtons按钮，Int32单击）在System.Windows.Forms.Control.WndProc（Message＆m）在System.Windows.Forms.ButtonBase.WndProc（Message＆m）在System.Windows.Forms.Button.WndProc（Message＆m）在System.Windows.Forms.NativeWindow.DebuggableCallback（IntPtr hWnd，Int32 msg，IntPtr wparam，IntPtr lparam）在System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW（MSG＆msg）在System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop（IntPtr dwComponentID，Int32原因，Int32 pvLoopData）在System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner（Int32原因，ApplicationContext上下文）在System.Windows.Forms.Application.ThreadContext.RunMessageLoop（Int32原因，ApplicationContext上下文）在Z：\ mike \ Downloads \ Adobe \ Acrobat DC SDK \ Version 1 \ InterAppCommunicationSupport \ C＃Samples \ JSObjectControlCS \ JSObjectControlCS \ Program.cs：第17行的JSObjectControlCS.Program.Main（）中

内部异常1： COMException：类型不匹配。（来自HRESULT的异常：0x80020005（DISP_E_TYPEMISMATCH））

Type.InvokeMember在扩展方法内抛出“ COMException：类型不匹配”

0 个答案: