将字符串和字节数组连接到非托管内存中

发布于 2024-08-28 00:29:49 字数 1310 浏览 9 评论 0原文

这是我的最后一个问题的后续问题。

我的位图图像现在有一个 byte[] 值。最终，我将向打印后台处理程序传递一个格式为 String.Format("GW{0},{1},{2},{3},", X, Y, stride, _Bitmap.Height ) + 我的二进制数据； 我正在使用中的 SendBytesToPrinter 命令在这里。

这是到目前为止将其发送到打印机的代码

public static bool SendStringPlusByteBlockToPrinter(string szPrinterName, string szString, byte[] bytes)
{
    IntPtr pBytes;
    Int32 dwCount;
    // How many characters are in the string?
    dwCount = szString.Length;
    // Assume that the printer is expecting ANSI text, and then convert
    // the string to ANSI text.
    pBytes = Marshal.StringToCoTaskMemAnsi(szString);
    pBytes = Marshal.ReAllocCoTaskMem(pBytes, szString.Length + bytes.Length);
    Marshal.Copy(bytes,0, SOMTHING GOES HERE,bytes.Length); // this is the problem line
    // Send the converted ANSI string + the concatenated bytes to the printer.
    SendBytesToPrinter(szPrinterName, pBytes, dwCount);
    Marshal.FreeCoTaskMem(pBytes);
    return true;
}

我的问题是我不知道如何将我的数据附加到字符串的末尾。任何帮助将不胜感激，如果我这样做完全错误，我可以采用完全不同的方式（例如，在移动到非托管空间之前以某种方式将二进制数据连接到字符串上。PS

）第二个问题，ReAllocCoTaskMem 是否会将调用之前位于其中的数据移动到新位置？

原文

This is a followup to my last question.

I now have a byte[] of values for my bitmap image. Eventually I will be passing a string to the print spooler of the format String.Format("GW{0},{1},{2},{3},", X, Y, stride, _Bitmap.Height) + my binary data; I am using the SendBytesToPrinter command from here.

Here is my code so far to send it to the printer

public static bool SendStringPlusByteBlockToPrinter(string szPrinterName, string szString, byte[] bytes)
{
    IntPtr pBytes;
    Int32 dwCount;
    // How many characters are in the string?
    dwCount = szString.Length;
    // Assume that the printer is expecting ANSI text, and then convert
    // the string to ANSI text.
    pBytes = Marshal.StringToCoTaskMemAnsi(szString);
    pBytes = Marshal.ReAllocCoTaskMem(pBytes, szString.Length + bytes.Length);
    Marshal.Copy(bytes,0, SOMTHING GOES HERE,bytes.Length); // this is the problem line
    // Send the converted ANSI string + the concatenated bytes to the printer.
    SendBytesToPrinter(szPrinterName, pBytes, dwCount);
    Marshal.FreeCoTaskMem(pBytes);
    return true;
}

My issue is I do not know how to make my data appended on to the end of the string. Any help would be greatly appreciated, and if I am doing this totally wrong I am fine in going a entirely different way (for example somehow getting the binary data concatenated on to the string before the move to unmanaged space.

P.S.
As a second question, will ReAllocCoTaskMem move the data that is sitting in it before the call to the new location?

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苄①跕圉湢 2024-09-04 00:29:49

我建议您尽可能留在受管理的空间内。使用 Encoding.ASCII< 将字符串转换为字节数组/a>，连接两个字节数组，然后使用结果调用本机方法。

byte[] ascii = Encoding.ASCII.GetBytes(szString);

byte[] buffer = new buffer[ascii.Length + bytes.Length];
Buffer.BlockCopy(ascii, 0, buffer, 0, ascii.Length);
Buffer.BlockCopy(bytes, 0, buffer, ascii.Length; bytes.Length);

...
bool success = WritePrinter(printer, buffer, buffer.Length, out written);
...

和

[DllImport("winspool.drv", EntryPoint = "WritePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool WritePrinter(IntPtr hPrinter, byte[] pBytes, int dwCount, out int dwWritten);

I recommend you try to stay in managed space as much as possible. Convert the string to a byte array using Encoding.ASCII, concatenate the two byte arrays and then invoke the native method with the result.

byte[] ascii = Encoding.ASCII.GetBytes(szString);

byte[] buffer = new buffer[ascii.Length + bytes.Length];
Buffer.BlockCopy(ascii, 0, buffer, 0, ascii.Length);
Buffer.BlockCopy(bytes, 0, buffer, ascii.Length; bytes.Length);

...
bool success = WritePrinter(printer, buffer, buffer.Length, out written);
...

with

[DllImport("winspool.drv", EntryPoint = "WritePrinter", SetLastError = true, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
public static extern bool WritePrinter(IntPtr hPrinter, byte[] pBytes, int dwCount, out int dwWritten);

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