問題描述

我正在嘗試將我的位圖保存到 MemoryStream - 這段代碼有什么問題?為什么它讓我argumentnullexception ?

I'm trying to save my Bitmap to MemoryStream - what wrong in this code? Why it gets me argumentnullexception ??

private void insertBarCodesToPDF(Bitmap barcode)
    {

            .......
            MemoryStream ms = new MemoryStream();
            barcode.Save(ms, System.Drawing.Imaging.ImageFormat.MemoryBmp); //<----
            byte [] qwe = ms.ToArray();
            .......

    }

UPD: StackTraceSystem.Drawing.Image.Save(流流，ImageCodecInfo 編碼器，EncoderParameters 編碼器參數)在 WordTest.FormTestWord.insertBarCodesToPDF(位圖條碼)

UPD: StackTrace System.Drawing.Image.Save(Stream stream, ImageCodecInfo encoder, EncoderParameters encoderParams) in WordTest.FormTestWord.insertBarCodesToPDF(Bitmap barcode)

推薦答案

我相信您的問題與您嘗試保存到 MemoryStream 的圖像類型有關.根據此代碼項目文章:動態生成圖標(安全)，一些 ImageFormat類型沒有必要的編碼器來允許保存功能保存為該類型.

I believe that your problem is related to the type of image you are trying to save to the MemoryStream as. According to this Code Project article: Dynamically Generating Icons (safely), some of the ImageFormat types do not have the necessary encoder to allow the Save function to save as that type.

我運行以下命令來確定哪些類型有效，哪些無效:

I ran the following to determine which types did and didn't work:

System.Drawing.Bitmap b = new Bitmap(10, 10);
foreach (ImageFormat format in new ImageFormat[]{
          ImageFormat.Bmp, 
          ImageFormat.Emf, 
          ImageFormat.Exif, 
          ImageFormat.Gif, 
          ImageFormat.Icon, 
          ImageFormat.Jpeg, 
          ImageFormat.MemoryBmp,
          ImageFormat.Png,
          ImageFormat.Tiff, 
          ImageFormat.Wmf}) 
{
  Console.Write("Trying {0}:", format);
  MemoryStream ms = new MemoryStream();
  bool success = true;
  try 
  {
    b.Save(ms, format);
  }
  catch (Exception) 
  {
    success = false;
  }
  Console.WriteLine("	{0}", (success ? "works" : "fails"));
}

結果如下:

Trying Bmp:       works
Trying Emf:       fails
Trying Exif:      fails
Trying Gif:       works
Trying Icon:      fails
Trying Jpeg:      works
Trying MemoryBMP: fails
Trying Png:       works
Trying Tiff:      works
Trying Wmf:       fails

有一個 Microsoft KB 文章，其中指出某些 ImageFormat類型是只讀的.

There is a Microsoft KB Article which states that some of the ImageFormat types are read-only.

這篇關于參數空異常位圖保存到內存流的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！