Parameter not valid C# when loading blob from MySQL

Question

this is my code:

        conn.Open();
        MySqlCommand cmd; MySqlDataAdapter da;
        String qry = $"SELECT email, image FROM users WHERE nickname='{textBox1.Text}'";
        cmd = new MySqlCommand(qry, conn);
        da = new MySqlDataAdapter(cmd);
        DataTable table = new DataTable();
        da.Fill(table);
        label1.Text = table.Rows[0][0].ToString();
        byte[] img = (byte[])table.Rows[0][1];
        MemoryStream ms = new MemoryStream(img);
        pictureBox1.Image = Image.FromStream(ms);
        da.Dispose();
        conn.Close();

I need to upload a blob picture from the Mysql database when i try to do this, i have a problem: "Parameter is not valid" Please helo

Does this answer your question? [Returning image created by Image.FromStream(Stream stream) Method](https://stackoverflow.com/questions/25187162/returning-image-created-by-image-fromstreamstream-stream-method) — Trevor, Feb 11 '20 at 18:44
¯\\_(ツ)_/¯ `No. I tried this` please add *this attempt* to your post including any errors so we can further help. — Trevor, Feb 11 '20 at 18:47
Fair enough, maybe some one else could chime in to help; good luck ;) — Trevor, Feb 11 '20 at 18:51

score 3 · Accepted Answer · answered Feb 11 '20 at 19:27

Welcome to Stackoverflow. I see that you want to get an image from the database. First, check if the image is inserted correctly. A right way to do it is to convert the image to a byte[] array than send it as a parameter. This is how I did it:

static public void UpdateProfilePicture(int id,Image img)
    {
        using (MySqlConnection conn = new MySqlConnection(ConnectionString.connectionString))
        {
            conn.Open();
            using (MySqlCommand cmd = new MySqlCommand())
            {
                cmd.CommandText = "UPDATE Users SET UserProfilePicture = @img WHERE idUser = @id";
                cmd.Connection = conn;

                var userImage = ImageToByte(img);
                var paramUserImage = new MySqlParameter("@img", MySqlDbType.Blob, userImage.Length);

                paramUserImage.Value = userImage;

                cmd.Parameters.Add(paramUserImage);
                cmd.Parameters.AddWithValue("@id", id);

                cmd.ExecuteNonQuery();
            }
        }
    }

    private static byte[] ImageToByte(Image img)
    {
        ImageConverter converter = new ImageConverter();
        return (byte[])converter.ConvertTo(img, typeof(byte[]));
    }

If you manage your mysql database with MySqlWorbench you can click on the cell where you inserted the image and it will appear in a window in a byte array format. Also, you can see the whole image if you go through the upper tabs of the window(I think this method also works in PhpMyAdmin)(Or you can search the internet for a byte array to image converter website).

After that, if everything is fine, here is a code sample that will help you retrieve the image:

static public Image GetUserImageById(int id)
    {
        MySqlDataAdapter da;

        using (MySqlConnection conn = new MySqlConnection(ConnectionString.connectionString))
        {
            conn.Open();
            using (MySqlCommand cmd = new MySqlCommand())
            {
                cmd.CommandText = "SELECT UserProfilePicture FROM Users WHERE idUser = @id";
                cmd.Connection = conn;

                cmd.Parameters.AddWithValue("@id", id);

                da = new MySqlDataAdapter(cmd);

                DataTable table = new DataTable();

                da.Fill(table);

                byte[] img = (byte[])table.Rows[0][0];

                MemoryStream ms = new MemoryStream(img);

                Image image;

                if (ms.Length > 0) image = Image.FromStream(ms);
                else
                image = null;

                da.Dispose();

                return image;
            }
        }
    }

P.S: If the format of the image or the file you want to insert in the database is not in a byte array format, than you won`t be able to retreive it.

Parameter not valid C# when loading blob from MySQL

1 Answers1