Question

我在嵌入式HTML中有一个Base64图像，如何使用C＃或VB.net对其进行解码。

Answer 1

google.com＆gt; base64图像解码c＃＆gt; http://www.eggheadcafe.com/community/aspnet/2/39033/convert-base64-string-to-image.aspx

Byte[] bitmapData = Convert.FromBase64String(FixBase64ForImage(ImageText));
System.IO.MemoryStream streamBitmap = new System.IO.MemoryStream(bitmapData);
Bitmap bitImage = new Bitmap((Bitmap)Image.FromStream(streamBitmap));

public string FixBase64ForImage(string Image) { 
    System.Text.StringBuilder sbText = new System.Text.StringBuilder(Image,Image.Length);
    sbText.Replace("\r\n", String.Empty); sbText.Replace(" ", String.Empty); 
    return sbText.ToString(); 
}

Answer 2

使用Convert.FromBase64String获取代表图像二进制文件的byte[]。

然后，您可以将生成的byte[]保存到文件中。

Answer 3

将嵌入的图像剪切成字符串。使用WebClient可能是您最好的选择。使用Convert.FromBase64String()将base64字符串转换为字节数组。使用MemoryStream和Image.FromStream()重新构建图像对象。

Answer 4

在上面的示例中，内存流尚未处理这可能会导致内存泄漏。所以基本思路是转换为 base64string到bytearray []到图像或位图图像创建可以通过内存流完成一个完美的例子试试这个链接 http://www.dailycoding.com/Posts/convert_image_to_base64_string_and_base64_string_to_image.aspx

Answer 5

这是我的解决方案，也许对您有帮助：

var lTest12 = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAYAAAAGCAYAAADgzO9IAAAAlklEQVQImS3DPwqCUAAH4HeVelG3cHB39hAOLnUAj+BSk4NDXcTNQaLsD7wwbLCCFyiIpObv11AffOK2WSNbzIezaSKdSB7kryi15iPdIw9DXFwXJ8NAKiXFp+9ZVxVfRcEiSZAHAZTjQJAkAL6bhqXWfCqF62o5CP6hbVFGETLPw9GyINB1qOMYd9+Hsm3spjNsR2N+AW4acROELpkYAAAAAElFTkSuQmCC";
Base64Helper
    .Analyze(lTest12)
    .Save2File(new FileInfo(@"C:\tmp\_vvv.ccc"));

public class Base64Helper
{
    public const string SearchToken = "base64,";
    public byte[] DecodedBase64;
    public string FileType;

    private Base64Helper(){}

    /// <summary>
    /// "data:image/jpeg;base64,"
    /// Removes preambleand cleans base64 encoded file content.
    /// Collects the file type if present.
    /// </summary>
    public static Base64Helper Analyze(string pBase64Str)
    {
        var lRet = new Base64Helper();
        var lStringBuilder = new StringBuilder(pBase64Str, pBase64Str.Length);
        lStringBuilder.Replace("\r\n", string.Empty);
        lStringBuilder.Replace(" ", string.Empty);

        var lTokenIndex = lStringBuilder.IndexOf(SearchToken);
        var lSplitIndex = lStringBuilder.IndexOf("/") + 1;
        var lFileTypeLength = lTokenIndex - lSplitIndex - 1;

        if (lSplitIndex > 0 && lFileTypeLength > 0)
            lRet.FileType = lStringBuilder.ToString(lSplitIndex, lFileTypeLength);

        var lStart = lTokenIndex + SearchToken.Length;
        if (lStart > -1)
            lStringBuilder.Remove(0, lStart);

        lRet.DecodedBase64 = Convert.FromBase64String(lStringBuilder.ToString());
        return lRet;
    }

    /// <summary>
    /// Saves the analyzed base64 content to the given file.
    /// if the file type of the base64 is present (default=true)
    /// the file type for the given file will be adjusted accordingly
    /// </summary>
    public void Save2File(FileInfo pSaveToFile, bool pAdjustFileType = true)
    {
        var lFile = pSaveToFile;
        if(pAdjustFileType && string.IsNullOrWhiteSpace(FileType) == false)
            lFile = pSaveToFile.ChangeExtension("." + FileType);

        //FileSystemHelper.EnsureDirectoryExistence(lFile);

        if (lFile.Exists)
            lFile.Delete(); //FileSystemHelper.Delete(lFile);

        using (var lFileStream = lFile.Open(FileMode.CreateNew, FileAccess.ReadWrite, FileShare.ReadWrite))
            lFileStream.Write(DecodedBase64, 0, DecodedBase64.Length);
    }

    //Edit: Forgot this here:
    public static int IndexOf(this StringBuilder pThis, string pSearchString, int pStartIndex = 0)
    {
        // Note: This does a StringComparison.Ordinal kind of comparison.
        if (pThis == null)
            throw new ArgumentNullException("pThis");

        if (pSearchString == null)
            pSearchString = string.Empty;

        for (var lIndex = pStartIndex; lIndex < pThis.Length; lIndex++)
        {
            int j;
            for (j = 0; j < pSearchString.Length && lIndex + j < pThis.Length && pThis[lIndex + j] == pSearchString[j]; j++) ;
            if (j == pSearchString.Length)
                return lIndex;
        }

        return -1;
    }
}

解码Base64图像

5 个答案: