问题:

I'm trying to create an image from a pdf using GhostScript. Here is my code:

GhostscriptWrapper.ConvertToBMP(inputPDFFilePath, outputBMPFilePath);

And here's my GhostscriptWrapper class:

public class GhostscriptWrapper {     public static void ConvertToBMP(string inputPath, string outputPath)     {         CallAPI(GetArgs(inputPath, outputPath));     }      private static void CallAPI(string[] args)     {         IntPtr ptr;         CreateAPIInstance(out ptr, IntPtr.Zero);         InitAPI(ptr, args.Length, args);         Cleanup(ptr);     }      private static void Cleanup(IntPtr gsInstancePtr)     {         ExitAPI(gsInstancePtr);         DeleteAPIInstance(gsInstancePtr);     }              [DllImport("gsdll32.dll", EntryPoint="gsapi_new_instance")]     private static extern int CreateAPIInstance(out IntPtr pinstance,         IntPtr caller_handle);      [DllImport("gsdll32.dll", EntryPoint="gsapi_delete_instance")]     private static extern void DeleteAPIInstance(IntPtr instance);      [DllImport("gsdll32.dll", EntryPoint="gsapi_exit")]     private static extern int ExitAPI(IntPtr instance);                      [DllImport("gsdll32.dll", EntryPoint="gsapi_init_with_args")]     private static extern int InitAPI(IntPtr instance, int argc,         string[] argv);      private static string[] GetArgs(string inputPath, string outputPath)     {         return new string[] { "-dNOPAUSE", "-dBATCH", "-dSAFER",             "-dTextAlphaBits=4", "-dGraphicsAlphaBits=4", "-sDEVICE=bmp16m",              string.Format("-r{0}x{1}", 0x48, 0x48), "-dEPSCrop",              string.Format("-sOutputFile={0}", outputPath), inputPath };     } }

My problem is that when I run my code on my page, I get this error:

Unable to load DLL 'gsdll32.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E)

I have the actual dll file, I thought maybe I just need to add a reference to my bin folder, but when I try that, I get this error:

A reference to 'D:\gsdll32.dll' could not be added. No type libraries were found in the component

So I'm kind of stuck - I have the dll, but I have no idea how to reference it. Anyone know what I need to do?

回答1:

In Package Manager Console type: Install-Package Ghostscript.Net

回答2:

As I understand it, you can't just 'add a reference' to a DLL, unless possibly the DLL was written for C# or .NET, which Ghostscript is not, its written in C.

You need to use the Win32 API call 'LoadLibrary' or whatever the C#/.NET equivalent is.

Your first error looks like the DLL simply can't be found, have you got a copy of the DLL in the current directory when you start the application ?