Getting error retrieving sql image from c# application

Question

I'm getting an error when trying to load and display a table of images:

data:image/jpg;base64,U3lzdGVtLkJ5dGVbXQ== ' cannot load image because of an error'

My SQL DB has a FileName(nvarhcar) Content(image) and ContentType (nvarchar)

Hopefully someone can help me learn why the image is not displaying. Thanks

Update c# to load image

        protected void Page_Load(object sender, EventArgs e)
        {
            if (Session["User"] == null)
                Response.Redirect("../Login.aspx");

            sqlcon.Open();
            SqlCommand cmd = sqlcon.CreateCommand();
            cmd.CommandType = CommandType.Text;
            cmd.CommandText = "SELECT * FROM BluePrints";

            cmd.ExecuteNonQuery();


            DataTable dt = new DataTable();
            SqlDataAdapter da = new SqlDataAdapter(cmd);
            da.Fill(dt);
            gvImages.DataSource = dt;
            gvImages.DataBind();

            sqlcon.Close();
        }

        protected void OnRowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                DataRowView dr = (DataRowView)e.Row.DataItem;
                string imageUrl = "data:image/jpg;base64," + 
                Convert.ToBase64String((byte[])dr["Content"]);
                (e.Row.FindControl("Image1") as Image).ImageUrl = imageUrl;
            }
        }
    }
}

  <asp:GridView ID="gvImages" runat="server" AutoGenerateColumns="false" OnRowDataBound="OnRowDataBound" Height="192px" Width="915px">
    <Columns>
      <asp:BoundField DataField="ID" HeaderText="ID" />
      <asp:BoundField DataField="FileName" HeaderText="Name" />
      <asp:TemplateField HeaderText="Image">
        <ItemTemplate>
          <asp:Image ID="Image1" runat="server" />
        </ItemTemplate>
      </asp:TemplateField>
    </Columns>
  </asp:GridView>
  <div id="dialog" style="display: none">
  </div>
  <br />
  <br />
  <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js">
  </script>
  <link rel="stylesheet" href="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.24/themes/start/jquery-ui.css" />
  <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.24/jquery- 
       ui.min.js"></script>
  <script type="text/javascript">
    $(function() {
      $("#dialog").dialog({
        autoOpen: false,
        modal: true,
        height: 600,
        width: 600,
        title: "Zoomed Image"
      });
      $("[id*=gvImages] img").click(function() {
        $('#dialog').html('');
        $('#dialog').append($(this).clone());
        $('#dialog').dialog('open');
      });
    });
  </script>
</asp:Content>

Insert code

protected void UploadButton_Click(object sender, EventArgs e)
    {

        FileInfo fi = new FileInfo(FileUploadControl.FileName);
        byte[] documentContent = FileUploadControl.FileBytes;

        string name = fi.Name;

        if (FileUploadControl.HasFile)
        {
            try
            {
                if (FileUploadControl.PostedFile.ContentType == "image/jpeg")
                {
                    if (FileUploadControl.PostedFile.ContentLength < 102400)
                    {

                        StatusLabel.Text = "Upload status: File uploaded!";

                        using (SqlConnection sqlcon = new SqlConnection(con))
                        {

                            sqlcon.Open();
                            SqlCommand cmd = sqlcon.CreateCommand();
                            cmd.CommandType = CommandType.Text;
                            cmd.CommandText = "INSERT INTO BluePrints (ID_Dev, PlotID, FileName, Content) VALUES  (' " + DropDownList1.SelectedValue + " ', '" + DropDownList2.SelectedValue + "', '" + name + "', '" + documentContent + "')";

                            cmd.ExecuteNonQuery();
                        }
                    }

                    else
                        StatusLabel.Text = "Upload status: The file has to be less than 100 kb!";
                }
                else
                    StatusLabel.Text = "Upload status: Only JPEG files are accepted!";

            }
            catch (Exception ex)
            {
                StatusLabel.Text = "Upload status: The file could not be uploaded. The following error occured: " + ex.Message;
            }

        }

''data:image/jpg;base64,U3lzdGVtLkJ5dGVbXQ=='' cannot be displayed, because it contains errors. — Watsyyy
– Watsyyy, Commented May 6, 2019 at 12:40
When I load the page, there is a small image icon, when i right click and view in another tab I receive that on a black background. — Watsyyy
– Watsyyy, Commented May 6, 2019 at 12:41
Try using the correct content type: image/jpeg. See for instance here... — user1429080
– user1429080, Commented May 6, 2019 at 13:07
just tried that, getting the same error but just jpeg instead of jpg — Watsyyy
– Watsyyy, Commented May 6, 2019 at 13:19

Wiktor Zychla · Accepted Answer · 2019-05-06 13:27:58Z

1

Problem is that U3lzdGVtLkJ5dGVbXQ== decoded is System.Byte[] rather than anything that should be an image.

In other words, your code that displays the data is possibly fine. Instead, your data in the database is invalid. It should be actual byte array rather than a string that says it's a byte array.

answered May 6, 2019 at 13:27

Wiktor Zychla

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2 Comments

Watsyyy Over a year ago

I added the insert code, could you have a look at it for me please

Wiktor Zychla Over a year ago

The code is incorrect and insecure. You should always use parametrized queries. The byte[] parameter should be added like this.

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