Solved

Extracting blob data and binding to datagrid asp.net 1.1 vb.net

Posted on 2007-04-11
3
675 Views
Last Modified: 2012-05-05
Experts, I am trying to bind blob's do a datagrid which I have never done in asp.net 1.1.  We have a database table that stores pdf's, docs, and gif's as blobs.  How do I extract blob's and bind it to a datagrid?
What I would like to do in the datagrid is have a hyper link column that when clicked displays the blob in its format as doc, pdf, gif etc.  Any ideas?
0
Comment
Question by:tentavarious
  • 2
3 Comments
 
LVL 4

Expert Comment

by:jasco4617
ID: 18892442
Tentavarious,

You would need to have a page, lets call it download.aspx and pass it a document ID that would be the the primary key for the column that has the stored blob data.

you would then need to have a query that pulls that information from the database and use that data to modify the http header for the request and stream the blob data.  See the below example.

--------
        Byte[] content = new Byte[0];
        String filename = "";
        String contentType = "";

        Response.ContentType = contentType;
        Response.AddHeader("Content-Disposition", "attachment; filename=" + filename);
        Response.BinaryWrite(content);
        Response.End();
-------

You would set the appriate variable information from what was returned in your query.   for this to work correctly, you must have the contentType (mime type) or else the browser will not know how to work with the data.

I hope this answers your question and points you in the right direction.

- pat
0
 

Author Comment

by:tentavarious
ID: 18897912
i was actually looking for maybe and example of using a datareader or dataset to read in the blob column.  Is there something special I need to do?
0
 
LVL 4

Accepted Solution

by:
jasco4617 earned 250 total points
ID: 18898575
Here is an example from .net 2.0....i am not sure if this is the same with 1.1 or not though (i think it is, give it a shot):




protected void Page_Load(object sender, EventArgs e)
    {
        String doc = Request.QueryString["doc"];
        try
        {
            Int32.Parse(doc);
        }
        catch
        {
            Response.Redirect("Default.aspx");
        }

        SqlConnection conn = new SqlConnection(WebConfigurationManager.ConnectionStrings["SQLConnString"].ConnectionString);
        SqlCommand cmd = new SqlCommand("SELECT files.*, fileTypes.* FROM files INNER JOIN fileTypes ON files.typeID = fileTypes.typeID WHERE fileID=@fileID", conn);
        cmd.Parameters.Add("@fileID", SqlDbType.Int).Value = doc;
        cmd.Connection.Open();
        SqlDataReader reader = cmd.ExecuteReader();
        Byte[] content = new Byte[0];
        String filename = "";
        String contentType = "";
        if (reader.HasRows)
        {
            while (reader.Read())
            {
                contentType = reader.GetValue(6).ToString();

                //content = new Byte[reader.GetInt32(7)];
                content = reader.GetSqlBytes(5).Buffer;
                //reader.GetBytes(5, 0, content, 0, reader.GetInt32(7));
                filename = reader.GetValue(1).ToString();
            }
        }

        cmd.Connection.Close();

        Response.ContentType = contentType;
        Response.AddHeader("Content-Disposition", "attachment; filename=" + filename);
        Response.BinaryWrite(content);
        Response.End();
    }
0

Featured Post

ScreenConnect 6.0 Free Trial

Discover new time-saving features in one game-changing release, ScreenConnect 6.0, based on partner feedback. New features include a redesigned UI, app configurations and chat acknowledgement to improve customer engagement!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

In this Article, I will provide a few tips in problem and solution manner. Opening an ASPX page in Visual studio 2003 is very slow. To make it fast, please do follow below steps:   Open the Solution/Project. Right click the ASPX file to b…
Sometimes in DotNetNuke module development you want to swap controls within the same module definition.  In doing this DNN (somewhat annoyingly) swaps the Skin and Container definitions to the default admin selections.  To get around this you need t…
Along with being a a promotional video for my three-day Annielytics Dashboard Seminor, this Micro Tutorial is an intro to Google Analytics API data.
Although Jacob Bernoulli (1654-1705) has been credited as the creator of "Binomial Distribution Table", Gottfried Leibniz (1646-1716) did his dissertation on the subject in 1666; Leibniz you may recall is the co-inventor of "Calculus" and beat Isaac…

777 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question