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上载预览图像时获取“base-64字符数组或字符串的长度无效”

asp.net-mvc c#

donprecious iyeritufu · 技术社区 · 6 年前

这个 Base64String 使用的参数开始于:

“数据:image/jpeg;base64,/9j/4aaqskzjrgabaqaaqabad/2wbdaaebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqebaqeb

public bool UploadAvatar(string UserID, string Base64String)
{
    if (string.IsNullOrEmpty(Base64String))
    {
        ReturnMessage = "Profile picture upload failed. No data from photo!";
        return false;
    }

    if (Base64ImageToFile(Base64String, filename, System.Drawing.Imaging.ImageFormat.Jpeg))
    {
        ReturnMessage = "Profile picture uploaded successfully!";
        return true;
    }

    ReturnMessage = "Failure uploading your profile picture!";
    return false;
}

public bool Base64ImageToFile(string Base64String, string SaveAs, System.Drawing.Imaging.ImageFormat Format)
{
    try
    {
        //Remove this part "data:image/jpeg;base64,"
        Base64String = Base64String.Split(',')[1];
       //Base64String = "/9j/4AAQSkZJRgABAQAAAQABAAD/2wBDAAEBAQEBAQEBAQEBAQEBAQEBAQEBAQEBAQ......"

        //This is where the error occurs

        byte[] bytes = Convert.FromBase64String(Base64String);

        Image image;
        using (var ms = new MemoryStream(bytes))
        {
            image = Image.FromStream(ms);
        }
        image.Save(SaveAs, Format);
        return true;
    }
    catch (Exception ex)
    {
        ReturnMessage = ex.Message;
        return false;
    }
}

1 回复 | 直到 6 年前

Prashant Pimpale Dila Gurung 6 年前

    public void GetImage(string imageString)
    {
        string imageStringToConvertIntoImage = "";

        // Check the Base64 string before remove the starting extension like: `data:image/jpeg;base64,`
        if (imageString.Contains(@"data:image/jpeg;base64,"))
        {
            imageStringToConvertIntoImage = imageString.Split(',')[1];
        }
        else
        {
            imageStringToConvertIntoImage = imageString;
        }

        // Image path where do you want to store images after convert
        string path = @"E:\\Temp\";

        // Check if path is exists or not, If not then create
        if (!Directory.Exists(path))
        {
            Directory.CreateDirectory(path);
        }

        if (!string.IsNullOrEmpty(imageStringToConvertIntoImage))
        {
          // Replace - with +
            string converted = imageStringToConvertIntoImage.Replace('-', '+');
          // From above modified string replace _ with /
            converted = converted.Replace('_', '/');

            using (MemoryStream ms = new MemoryStream(Convert.FromBase64String(imageStringToConvertIntoImage)))
            {
                var pageFilePath = Path.Combine(path, string.Format(DateTime.Now.Ticks.ToString() + "-Image.jpg"));
                // Draw image from memory stream and use Save method to save image file with specified format
                System.Drawing.Image image = System.Drawing.Image.FromStream(ms, true);
                image.Save(pageFilePath, ImageFormat.Jpeg);
            }
        }
    }