System.NullReferenceException: Object reference not set to an instance of an object - c#

In this code i wanted to save the image in picturebox1 in database using linqtosql ..... but getting some exceptions in converting a image to byte array
Exception is "System.NullReferenceException: Object reference not set to an instance of an object."
private void button1_Click(object sender, EventArgs e)
{
DataClasses1DataContext dc = new DataClasses1DataContext();
try
{
string signname = textBox1.Text;
string imageurl = textBox2.Text;
pictureBox1.ImageLocation = imageurl;
// byte[] file_byte = new byte[1000];
// Image newimage = new Image(pictureBox1.Image);
///Error comes here
byte[] file_byte = ImageToByteArray(pictureBox1.Image);
System.Data.Linq.Binary file_binary = new System.Data.Linq.Binary(file_byte);
Sign_Table obj = new Sign_Table()
{
Sign_Name = signname,
Sign_Image = file_binary,
};
dc.Sign_Tables.InsertOnSubmit(obj);
}
finally
{
dc.SubmitChanges();
}
}
private byte[] ImageToByteArray(Image imageIn )
{
using (MemoryStream ms = new MemoryStream())
{
// Error comes here
imageIn.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
return ms.ToArray();
}
}

I suspect the problem is that pictureBox.Image is null when you reference it. You are setting pictureBox.ImageLocation but not actually loading the image.
Add a call to pictureBox.Load() immediately after setting pictureBox.ImageLocation.

When you create the Memorystream, you have to associate with bytes[], for example
byte[] buf = new byte[4096];
Then you could you
using (MemoryStream ms = new MemoryStream(buf))
So calculate an upper bound for the image size in bytes, and then associate a MemoryStream to an array containing that many bytes.

Related

How to insert and retrieve an image from C# to/from a database? [duplicate]

This question already has answers here:
Byte array to image conversion
(14 answers)
Display image from byte[ ]
(1 answer)
Closed 5 years ago.
I'm new to WPF programming and Microsoft SQL server. I want to insert and retrieve an image to/from a database. I learned about converting an image (Windows.Controls.Image) to byte[] and storing it to a database, but I couldn't convert from byte[] to Image back to display it in a WPF window.
private Image byteArrayToImage(byte[] arr)
{
MemoryStream stream = new MemoryStream();
stream.Write(arr, 0, arr.Length);
stream.Position = 0;
System.Drawing.Image img = System.Drawing.Image.FromStream(stream); // Exception
BitmapImage returnImage = new BitmapImage();
returnImage.BeginInit();
MemoryStream ms = new MemoryStream();
img.Save(ms, System.Drawing.Imaging.ImageFormat.Bmp);
ms.Seek(0, SeekOrigin.Begin);
returnImage.StreamSource = ms;
returnImage.EndInit();
Image ans = new Image();
ans.Source = returnImage;
return ans;
}
Output:
System.ArgumentException: 'Parameter is not valid.'
private byte[] imageToArray(System.Drawing.Image img) // Work well
{
MemoryStream ms = new MemoryStream();
FileInfo fi = new FileInfo(tempData); // File name
img.Save(ms, System.Drawing.Imaging.ImageFormat.Png);
byte[] pic = ms.ToArray();
return pic;
}
first, create a static class for your PictureHelper. You must import the BitmapImage that is used in WPF, i think its the using System.Drawing.Imaging;
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;
using System.Windows;
using System.Windows.Forms;
using System.Windows.Threading;
using Application = System.Windows.Forms.Application;
using Size = System.Drawing.Size;
public static class PictureHelper
{
public static BitmapImage GetImage(object obj)
{
try
{
if (obj == null || string.IsNullOrEmpty(obj.ToString())) return new BitmapImage();
#region Picture
byte[] data = (byte[])obj;
MemoryStream strm = new MemoryStream();
strm.Write(data, 0, data.Length);
strm.Position = 0;
Image img = Image.FromStream(strm);
BitmapImage bi = new BitmapImage();
bi.BeginInit();
MemoryStream ms = new MemoryStream();
img.Save(ms, ImageFormat.Bmp);
ms.Seek(0, SeekOrigin.Begin);
bi.StreamSource = ms;
bi.EndInit();
return bi;
#endregion
}
catch
{
return new BitmapImage();
}
}
public static string PathReturner(ref string name)
{
string filepath = "";
OpenFileDialog openFileDialog = new OpenFileDialog();
openFileDialog.Multiselect = false;
openFileDialog.Filter = #"Image Files(*.jpeg;*.bmp;*.png;*.jpg)|*.jpeg;*.bmp;*.gif;*.png;*.jpg";
openFileDialog.RestoreDirectory = true;
openFileDialog.Title = #"Please select an image file to upload.";
MiniWindow miniWindow = new MiniWindow();
miniWindow.Show();
if (openFileDialog.ShowDialog() == DialogResult.OK)
{
filepath = openFileDialog.FileName;
name = openFileDialog.SafeFileName;
}
miniWindow.Close();
miniWindow.Dispose();
return filepath;
}
public static string Encryptor(this string safeName)
{
string extension = Path.GetExtension(safeName);
string newFileName = String.Format(#"{0}{1}{2}", Guid.NewGuid(), DateTime.Now.ToString("MMddyyyy(HHmmssfff)"), extension);
newFileName = newFileName.Replace("(", "").Replace(")", "");
return newFileName;
}
public static Bitmap ByteToBitmap(this byte[] blob)
{
MemoryStream mStream = new MemoryStream();
byte[] pData = blob;
mStream.Write(pData, 0, Convert.ToInt32(pData.Length));
Bitmap bm = new Bitmap(mStream, false);
mStream.Dispose();
return bm;
}
public static byte[] BitmapToByte(this Image img)
{
byte[] byteArray = new byte[0];
using (MemoryStream stream = new MemoryStream())
{
img.Save(stream, ImageFormat.Png);
stream.Close();
byteArray = stream.ToArray();
}
return byteArray;
}
}
this is for retrieving the class (in my case, Candidate) with picture
public SortableBindingList<Candidate> RetrieveManyWithPicture(Candidate entity)
{
var command = new SqlCommand { CommandText = "RetrievePictureCandidates", CommandType = CommandType.StoredProcedure };
command.Parameters.AddWithValue("#CandidateId", entity.CandidateId).Direction = ParameterDirection.Input;
DataTable dt = SqlHelper.GetData(command); //this is where I retrieve the row from db, you have your own code for retrieving, so make sure it works.
var items = new SortableBindingList<Candidate>();
if (dt.Rows.Count <= 0) return items;
foreach (DataRow row in dt.Rows)
{
Candidate item = new Candidate();
item.CandidateId = row["CandidateId"].GetInt();
item.LastName = row["LastName"].GetString();
item.FirstName = row["FirstName"].GetString();
item.PictureId = row["PictureId"].GetInt();
item.PhotoType = PictureHelper.GetImage(row["Photo"]); //in my db, this is varbinary. in c#, this is byte[]
items.Add(item);
}
return items;
}
this is for uploading image from wpf to db which I used on my button
private void UploadButton_Click(object sender, EventArgs e)
{
string safeName = "";
string pathName = PictureHelper.PathReturner(ref safeName);
PictureViewModel vm = new PictureViewModel();
if (pathName != "")
{
safeName = safeName.Encryptor();
FileStream fs = new FileStream(pathName, FileMode.Open, FileAccess.Read);
byte[] data = new byte[fs.Length];
fs.Read(data, 0, Convert.ToInt32(fs.Length));
fs.Close();
PicNameLabel.Text = safeName;
vm.Entity.Name = safeName; //this is the byte[]
Bitmap toBeConverted = PictureHelper.ByteToBitmap(data); //convert the picture before sending to the db
vm.Entity.Photo = PictureHelper.BitmapToByte(toBeConverted);
vm.Entity.Path = pathName;
CandidatePictureBox.Image = toBeConverted;
vm.Insert(vm.Entity);
}
}
this is the method to save the picture
public bool Insert(Picture entity)
{
var command = new SqlCommand();
try
{
command.CommandText = "AddPicture";
command.CommandType = CommandType.StoredProcedure;
command.Parameters.AddWithValue("#Name", entity.Name).Direction = ParameterDirection.Input;
command.Parameters.AddWithValue("#Photo", entity.Photo).Direction = ParameterDirection.Input;
int result = SqlHelper.ExecuteNonQuery(command); //executenonquery will save the params to the db
return true;
}
catch (Exception)
{
return false;
}
}

BitmapEncoder Save Not Supported

I have the following code and I can't see anything wrong, any ideas on what the problem could be?
private static string SaveBaseImage( ZipArchive arc, DBImage image, int imageIndex )
{
using (var mem = new MemoryStream(image.Data))
{
var bmp = BitmapFrame.Create(mem);
//var bmp = BitmapFrame.Create(m‌​em, BitmapCreateOptions.‌​None, BitmapCacheOption.On‌​Load);
var codex = bmp.Decoder.CodecInfo;
var filename = $"{imageIndex}{codex.FileExtensions}";
var imagezip = arc.CreateEntry(filename,CompressionLevel.Optimal));
using (var imagestream = imagezip.Open())
{
SaveImage( bmp, imagestream);
}
return filename;
}
}
private static void SaveImage(BitmapFrame data, Stream saveStream)
{
var codex = data.Decoder.CodecInfo;
var encoder = BitmapEncoder.Create(codex.ContainerFormat);
encoder.Frames.Add(data);
encoder.Save(saveStream);
}
when I run it throws
System.NotSupportedException occurred HResult=-2146233067
Message=Specified method is not supported. Source=PresentationCore
StackTrace:
at System.Windows.Media.Imaging.BitmapEncoder.Save(Stream stream)
at FileFormatters.Export.SaveImage(BitmapFrame data, Stream saveStream)
InnerException: null
The MSDN page says
NotSupportedException :The Frames value that is passed to the encoder is null.
NotSupportedException :The Frames count is less than or equal to zero.
However frames count is 1 and data is not null
further info
arc declared as using (ZipArchive arc = new ZipArchive(stream, ZipArchiveMode.Create))
image.Data is byte[]
codex.FriendlyName = "PNG Decoder"
encoder.CodecInfo.FriendlyName = "PNG Encoder"
It seems to be necessary to write the image buffer to an intermediate MemoryStream, before it can be written to a ZipEntry Stream:
private static void SaveImage(BitmapFrame data, Stream saveStream)
{
var encoder = BitmapEncoder.Create(data.Decoder.CodecInfo.ContainerFormat);
encoder.Frames.Add(data);
using (var memoryStream = new MemoryStream())
{
encoder.Save(memoryStream);
memoryStream.Position = 0;
memoryStream.CopyTo(saveStream);
}
}

BitMapImage to byte and reverse

Since two days I try to manage my images in a WPF application but I have errors and errors errors, ...
The image is show in a System.Windows.Control.Image.
For this reason I try to work with variable BitMapImage.
Now I have the error : "Impossible to access close stream" and I can not find a solution.
I have created two function for convert :
public static BitmapImage ConvertToBitMapImage(byte[] bytes)
{
if (bytes == null || bytes.Length == 0) return null;
var image = new BitmapImage();
using (var mem = new MemoryStream(bytes))
{
mem.Position = 0;
image.BeginInit();
image.CreateOptions = BitmapCreateOptions.PreservePixelFormat;
image.CacheOption = BitmapCacheOption.OnLoad;
image.UriSource = null;
image.StreamSource = mem;
image.EndInit();
}
//image.Freeze();
return image;
}
public static byte[] ImageToByte(BitmapImage imageSource)
{
Stream stream = imageSource.StreamSource;
Byte[] buffer = null;
if (stream != null && stream.Length > 0)
{
using (BinaryReader br = new BinaryReader(stream))
{
buffer = br.ReadBytes((Int32)stream.Length);
}
}
return buffer;
}
In my object I have a property :
public BitmapImage MiniatureApp
{
get
{
if (IMAGES != null)
_MiniatureApp = Tools.BinaryImageConverter.ConvertToBitMapImage(IMAGES.IMAGE);
return _MiniatureApp;
}
set
{
if (this.IMAGES != null)
this.IMAGES.IMAGE = Tools.BinaryImageConverter.ImageToByte((BitmapImage)value);
else
{
IMAGES img = new IMAGES();
img.NOM = "";
img.IMAGE = Tools.BinaryImageConverter.ImageToByte((BitmapImage)value);
this.IMAGES = img;
}
NotifyPropertyChanged();
}
}
And in my main I do this :
FileStream fs = new FileStream(pathImage, FileMode.Open, FileAccess.Read);
byte[] data = new byte[fs.Length];
fs.Read(data, 0, System.Convert.ToInt32(fs.Length));
fs.Close();
VMAppareil.VMApp.CurrentAppareil.MiniatureApp = Tools.BinaryImageConverter.ConvertToBitMapImage(data);
Exist a solution for my problem or exist a best way to do this ?
Gobelet.
You can fix your solution replacing the ImageToByte method with the following (borrowed from https://stackoverflow.com/a/6597746/5574010)
public static byte[] ImageToByte(BitmapImage imageSource)
{
var encoder = new JpegBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(imageSource));
using (var ms = new MemoryStream())
{
encoder.Save(ms);
return ms.ToArray();
}
}
Your previous solution did not work because the ConvertToBitMapImage method close the stream that you assign to image.StreamSource as soon as your code exit the unit statement. When you call the ImageToByte method as part of the MiniatureApp setter the StreamSource will be close and you get an error.
I'm not really sure what you're doing with the getter-setter.
For getting a byte array from a file, I would have this:
public static byte[] FileToByteArray(string fileName)
{
byte[] fileData = null;
using (FileStream fs = new File.OpenRead(fileName))
{
var binaryReader = new BinaryReader(fs);
fileData = binaryReader.ReadBytes((int)fs.Length);
}
return fileData;
}
And once you have the bytes from that function, you can use ConvertToBitMapImage() and assign that to the Image.Source, like this:
byte[] bytes = FileToByteArray(fileName);
YourImage.Source = ConvertToBitMapImage(bytes);
I'm not sure why you would need to convert a BitmapImage into bytes, but you should be able to call your function directly for that:
BitmapImage bImg = new BitmapImage();
bImg.Source = ConvertToBitMapImage(bytes);
byte[] bytes = ImageToByte(bImg); // these should be the same bytes as went in
Set it up like this and step through the code to see where it snags. It's possible the bytes might need encoding when you grab it in ImageToByte().
But also, you don't just then set the byte[] directly to the IMAGES or this.IMAGES.IMAGE, because that isn't an Image object, it's a byte[]. Without knowing what your IMAGES model construct looks like with its property types, it's a little vague to know what is being set to what and why, but this seems like a bad idea to over-complicate what you should just do with function calls as it is needed, without a getter-setter and an IMAGES model in the way.

C# with ZXing.Net: Decoding the QR code

I'm new to C# and got problem with QR code decoding using ZXing.Net. The application launches with no errors, but I get nothing in the result string. I think the problem could be in RGBLuminanceSource().
private static byte[] ToByteArray(Image img)
{
byte[] byteArray = new byte[0];
using (MemoryStream stream = new MemoryStream())
{
img.Save(stream, System.Drawing.Imaging.ImageFormat.Bmp);
stream.Close();
byteArray = stream.ToArray();
}
return byteArray;
}
private void button1_Click(object sender, EventArgs e)
{
*** SOME OTHER CODE HERE ***
Bitmap BitmapImage = new Bitmap(#"D:\1.png");
QRCodeReader reader = new QRCodeReader();
LuminanceSource source = new RGBLuminanceSource(ToByteArray(BitmapImage), BitmapImage.Width, BitmapImage.Height);
var binarizer = new HybridBinarizer(source);
var binBitmap = new BinaryBitmap(binarizer);
string result = reader.decode(binBitmap).Text;
*** SOME OTHER CODE HERE ***
}
Just call function. Also, replace ... with your handling
public Result decode(Uri uri)
{
Bitmap image;
try
{
image = (Bitmap) Bitmap.FromFile(uri.LocalPath);
}
catch (Exception)
{
throw new FileNotFoundException("Resource not found: " + uri);
}
using (image)
{
LuminanceSource source;
source = new BitmapLuminanceSource(image);
BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
Result result = new MultiFormatReader().decode(bitmap);
if (result != null)
{
... code found
}
else
{
... no code found
}
return result;
}
}

How to convert varBinary into image or video when retrieved from database in C#

I am using visual studio 2010, (desktop application) and using LINQ to SQL to save image/video or audio files to database in dataType VarBinary (MAX). This I can do... Problem is, I can't get them and display them in xaml because I can't get the converting part correct. Here is what I have so far (though its not working);
private void bt_Click (object sender, RoutedEventArgs e)
{
databaseDataContext context = new databaseDataContext();
var imageValue = from s in context.Images
where s.imageID == 2
select s.imageFile;
value = imageValue.Single().ToString();
//convert to string and taking down to next method to get converted in image
}
public string value { get; set; }
public object ImageSource //taking from http://stackoverflow.com/
{
get
{
BitmapImage image = new BitmapImage();
try
{
image.BeginInit();
image.CacheOption = BitmapCacheOption.OnLoad;
image.CreateOptions = BitmapCreateOptions.IgnoreImageCache;
image.UriSource = new Uri(value, UriKind.Absolute);
image.EndInit();
Grid.Children.Add(image);
}
catch { return DependencyProperty.UnsetValue; } return image;
}
}
I not even sure if I am on the correct track? And I am assuming that video or audio is quite similar methods?
Since your image is stored in binary format in the database, you want to "stream" this into an image object by leveraging the MemoryStream object.
Looking at your code, your solution will look something like this:
BitmapImage bmpImage = new BitmapImage();
MemoryStream msImageStream = new MemoryStream();
msImageStream.Write(value, 0, value.Length);
bmpCardImage.BeginInit();
bmpCardImage.StreamSource = new MemoryStream(msImageStream.ToArray());
bmpCardImage.EndInit();
image.Source = bmpCardImage;
It's very easy, if you have a binary data and want to create an Image object, use this code:
public Image BinaryToImage(byte[] binaryData)
{
MemoryStream ms = new MemoryStream(binaryData);
Image img = Image.FromStream(ms);
return img;
}
If you already have the bytes, to verify that what you saved is correct you can save the bytes to a file and open it....
string tempFile = Path.GetTempFileName();
MemoryStream ms = new MemoryStream(bytes); //bytes that was read from the db
//Here I assume that you're reading a png image, you can put any extension you like is a file name
FileStream stream = new FileStream(tempFile + ".png", FileMode.Create);
ms.WriteTo(stream);
ms.Close();
stream.Close();
//And here we open the file with the default program
Process.Start(tempFile + ".png");
And later you can use the answer of Dillie-O and stream....
Dillie-O's code makes for a very nice extension method:
// from http://stackoverflow.com/questions/5623264/how-to-convert-varbinary-into-image-or-video-when-retrieved-from-database-in-c:
public static BitmapImage ToImage(this Binary b)
{
if (b == null)
return null;
var binary = b.ToArray();
var image = new BitmapImage();
var ms = new MemoryStream();
ms.Write(binary, 0, binary.Length);
image.BeginInit();
image.StreamSource = new MemoryStream(ms.ToArray());
image.EndInit();
return image;
}

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