C# retrieving image in db. Get Error Parameter in not valid

Question

I don't know what's wrong with my code in retrieving image in db. I insert image without using image path file cause the image provide by the cam.

Here's my code in inserting image in db

Image img = pictureBox1.Image;
MemoryStream memStream = new MemoryStream();
img.Save(memStream, ImageFormat.Bmp);
byte[] imageBt = memStream.ToArray();
query = "";
query += "INSERT INTO table(picture) VALUES ('" + imageBt + "')";
cmd = new MySqlCommand(query, con);
cmd.ExecuteNonQuery();
con.close();

Here's my code in retrieving image in db

query = "";
query += "SELECT picture FROM table WHERE id = '1'";
cmd = new MySqlCommand(query, con);
con.Open();
MemoryStream ms = new MemoryStream();
byte[] image = (byte[])cmd.ExecuteScalar();
ms.Write(image, 0, image.Length);
con.Close();
Bitmap bmp = new Bitmap(ms)
pictureBox1.Image = bmp; //Still get the Error here parameter is not valid

Is there anywrong process in saving image in database. Btw my image type in db is Blob. I don't know why it doesn't work in retrieving image it always thrown error. Thanks

i also try this one but i doesn't work also dr = cmd.ExecuteReader(); if (dr.Read()) { byte[] data = (byte[])dr["picture"]; MemoryStream ms = new MemoryStream(data); pictureBox1.Image = Image.FromStream(ms); } — issei-kun
– issei-kun, Commented Jul 5, 2016 at 15:58
Looks like you are trying to insert text. Use parameters to avoid sql injection and formatting issues. — LarsTech
– LarsTech, Commented Jul 5, 2016 at 16:01
How can you append the byte[] imageBt variable to a string? query += "INSERT INTO table(picture) VALUES ('" + imageBt + "')"; I think you want to insert a binary blob or something in hex, but not like this. Check what exact query is executed above, wouldn't wonder if its ".. VALUES (System.Byte[]) — Maximilian Gerhardt
– Maximilian Gerhardt, Commented Jul 5, 2016 at 16:02
Any time you have a question about a “thrown error” please include the error message. — Dour High Arch
– Dour High Arch, Commented Jul 5, 2016 at 16:30

Marc Gravell · Accepted Answer · 2016-07-05 16:01:39Z

2

When reading, you haven't rewound the stream. If you Write, you must set ms.Position = 0; afterwards. Or simpler: create the stream from the data, then you don't need to:

byte[] image = ...
var ms = new MemoryStream(image);

When writing, you seem to have injected the data directly. That... almost certainly won't work - in fact, you're probably writing System.Byte[] to the command. Ideally, use a parameter:

query = "INSERT INTO table(picture) VALUES (@blob)";
cmd = new MySqlCommand(query, con);
cmd.Parameters.AddWithValue("blob", imageBt);
cmd.ExecuteNonQuery();

(the exact syntax may change between RDBMS implementations)

answered Jul 5, 2016 at 16:01

Marc Gravell

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6 Comments

issei-kun Over a year ago

Thanks for answering this question really aprreciated it :). May i ask if do i need to change the way how i insert image in db? Thanks

Marc Gravell Over a year ago

@issei-kun yes; the code in the question doesn't insert the image into the DB. IIt inserts the string "System.Byte[]" every single time. I'm Guessing that isn't what you intended.

issei-kun Over a year ago

Yeah but how will i insert the image in db and retrieve it. It seems my pic in db when i try to retrieve it always throw error parameter is not valid. How will i fix it or what is the proper way of inserting image in db with blob type and retrieve it in picture box.

Marc Gravell Over a year ago

@issei-kun I've already answered these questions. And if you are using the sql shown in your question to insert into the DB: no, your image is not in the DB. The literal string System.Byte[] is what you will have stored every time. Not the contents.

issei-kun Over a year ago

so much better if i will not convert my image into byte[] array? and retrieve it by creating stream?

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