从MySQL数据库将图像另存为BLOB时参数无效

Question

I'm trying to get images saved in MySQL database as BLOB images into a picture box in my Windows application.

This is my code.

private Image GetFaceFromDB()
    {

    Image fetchedImage;

        if (rowNumber >= 0)
        {
            byte[] faceTobyte = (byte[])dataTable.Rows[rowNumber] 
            ["Image"];
            MemoryStream stream = new MemoryStream(faceTobyte);
            fetchedImage = Image.FromStream(stream); **//Error at this 
            line**
            return fetchedImage;
        }else
            {
                MessageBox.Show("There are no images in thedatabase,please 
                insert images.");
                return null;
            }
      }

This is the button click event

 private void btnFirst_Click(object sender, EventArgs e)
    {
    RefreshDBConnection();

    rowNumber = 0;
    pbTrainingSetImages.Image = GetFaceFromDB();
    tbUpdateFaceName.Text = dataTable.Rows[rowNumber]["Name"].ToString();
    lbFaceNumber.Text = (rowNumber + 1).ToString();
    if(pbTrainingSetImages.Image != null)
    {
        MessageBox.Show("You have reached the First image in the 
    database!");
    }

    }

I have also tried the following code

A

private void btnFirst_Click(object sender, EventArgs e)
   {

        RefreshDBConnection();
        rowNumber = 0;
        pbTrainingSetImages.Image = GetFaceFromDB();
        tbUpdateFaceName.Text = dataTable.Rows[rowNumber] 
 ["Name"].ToString();
        lbFaceNumber.Text = (rowNumber + 1).ToString();
        if(pbTrainingSetImages.Image != null)
        {
            MessageBox.Show("You have reached the First image in the 
        database!");
        }

   }

B

 private Image GetFaceFromDB()
        {

            Image fetchedImage;

            if (rowNumber >= 0)
            {
            byte[] faceTobyte= (byte[])dataTable.Rows[rowNumber["Image"];
                MemoryStream stream = new MemoryStream();
                stream.Position = 0;
                return fetchedImage = Image.FromStream(stream, false);
            }
            else
            {
                MessageBox.Show("There are no images in the database, please 
     insert 
                images.");
                return null;
            }
        }

C

  private Image GetFaceFromDB()
        {

        Image fetchedImage;

        if (rowNumber >= 0)
        {
          byte[] faceTobyte = (byte[])dataTable.Rows[rowNumber]["Image"];
            MemoryStream stream = new MemoryStream();
            stream.Position = 0;
            return fetchedImage = Image.FromStream(stream, false);
        }
        else
        {
        MessageBox.Show("There are no images in the database,please insert 
            images.");
            return null;
        }
       }

D

private Image GetFaceFromDB()
       {

            Image fetchedImage;

            if (rowNumber >= 0)
            {
                byte[] faceTobyte = (byte[])dataTable.Rows[rowNumber] 
                ["Image"];
                using(var stream = new  MemoryStream(faceTobyte))
                {
                    fetchedImage = Image.FromStream(stream);
                    return fetchedImage;
                }

            }
            else
            {
              MessageBox.Show("There are no images in the database, please 
                insert images.");
                return null;
            }
        }

I've also tried most of the answers provided in these Stack Overflow links:

• convert binary to bitmap using memory stream
• Image.MemoryStream : Parameter not valid
• Parameter not valid
• Byte Array to Image Conversion

This is the error message Parameter not valid at this line

fetchedImage = Image.FromStream(stream);

This is my Insert statement

 private void AddFacesToDB(Image inputImage, string inputLabel)
    {
    if (connection.State.Equals(ConnectionState.Closed))
    {
        connection.Open();
    }

    try
    {
        //convert the face image to byte format for storing in db
        byte[] facesToByte = ConvertFaceToDBFormat(inputImage);
        totalRows++;

        //At what location is the image being stored to
        MessageBox.Show($"Adding row {totalRows.ToString()}");

        //inserting the image into the row 
        MySqlCommand insertCommand = new MySqlCommand("insert into 
     testimages.image_information(FaceID, FaceNo, Name, Image) values('" + 
       totalRows.ToString() + "','" + totalRows.ToString() + "', '" + 
       tbSetFaceLabel.Text + "', @IMG)", connection);

        MySqlParameter imageParam = 
       insertCommand.Parameters.AddWithValue("@IMG","Image");
        imageParam.Value = facesToByte;
        imageParam.Size = facesToByte.Length;
        int rowAffected = insertCommand.ExecuteNonQuery();
        MessageBox.Show("Data Stored Successfully in " + 
        rowAffected.ToString() + " Rows");

    }catch(Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
    finally
    {
        RefreshDBConnection();
    }

    }

This is my database

Answer 1

I finally solved it. After spending 6 hours. Persistence pays. It was my Insert statement that the problem lied,

byte[] faceTobyte = (byte[])dataTable.Rows[rowNumber]["Image"];

I kept parsing "Image" into byte not knowing I wasn't parsing a valid image format. So I edited the my insert statement to this:

//At what location is the image being stored to
            MessageBox.Show($"Adding row {totalRows.ToString()}");

            //inserting the image into the row 
        MySqlCommand insertCommand = new MySqlCommand("insert into testimages.image_information(FaceID, FaceNo, Name, Image) 
            values(@faceid, @faceno, @name, @img)", connection);

            MySqlParameter imageParam;
            insertCommand.Parameters.Add("@faceid", MySqlDbType.Int16,25);
           insertCommand.Parameters.Add("@faceno", MySqlDbType.Int16, 25);
          insertCommand.Parameters.Add("@name", MySqlDbType.VarChar, 25);
            insertCommand.Parameters.Add("@img", MySqlDbType.Binary);

        insertCommand.Parameters["@faceid"].Value = totalRows.ToString();
        insertCommand.Parameters["@faceno"].Value = totalRows.ToString();
            insertCommand.Parameters["@name"].Value = tbSetFaceLabel.Text;
            insertCommand.Parameters["@img"].Value = facesToByte;
            int rowAffected = insertCommand.ExecuteNonQuery();
            MessageBox.Show("Data Stored Successfully in " 
            + rowAffected.ToString() + " Rows");

Now, the correct image format is being passed and the image displays in the picture box.