Retrieving DataTable from Memory Stream.

Question

I have a data table that is formatted from an array of Column Names, I.e.

        DataTable ThisTable = new DataTable();

        for (int i = 0; i <= col.GetUpperBound(0); i++)
        {
            try
            {
                ThisTable.Columns.Add(new DataColumn(col[i].ToString(), typeof(string)));
            }
            catch (Exception e)
            {
                MessageBox.Show("Uploader  Error"+e.ToString());
                return null; 
            }
        }

i then use a BinaryFormatter object to Serialize/Deserialize a memory stream so that I can read the data from the stream into a table. Essentially users will be uploading an excel sheet that will be read into a database. Although I realize that it is possible, I DO NOT want to write the sheet to disk then read it in.

However when I go to retrieve the datatable from the Deserialize() call, I dont get an error, however I get an empty DataSet.

Mem would be my memory stream object.

        BinaryFormatter bformat = new BinaryFormatter();
        bformat.Serialize(Mem, ThisTable);
        Mem.Seek(0, SeekOrigin.Begin);
        byte[] bt = Mem.ToArray();


        Stream s = new MemoryStream(bt);
        Mem.Position = 0;            
        s.Position = 0; 
        ThisTable = (DataTable)bformat.Deserialize(Mem); 
        DS.Tables.Add(ThisTable);

        return DS;

I don't think that's the way to go... there are much easier ways to do what you're talking about. — James Johnson, Sep 14 '11 at 19:45
When you say that you get an empty DataSet, do you mean DataSet.Tables == null? Or DataSet.Tables[0].Rows.Count == 0? — RoccoC5, Sep 14 '11 at 19:55
I meant that I have a data table from the Deserialize() call, but no rows. — Kwalke001, Sep 14 '11 at 19:57

score 0 · Answer 1 · edited May 23 '17 at 12:29

0

I would suggest using the OpenXml SDK to read the Excel file into the DataTable.

Take a look at the answer from M_R_H for an example:

From Excel to DataTable in C# with Open XML

You can also look at the answer from amurra here for another example:

reading Excel Open XML is ignoring blank cells

edited May 23 '17 at 12:29

Community

1
1

answered Sep 14 '11 at 19:53

James Johnson

45,496
8
73
110

score 0 · Answer 2 · answered Sep 14 '11 at 19:58

0

Unless there is an error in the sample code you posted, you aren't populating the DataTable with any data, you are just creating columns. You can add rows to the DataTable via DataTable.Rows.Add():

foreach(var o in myDataSource)
{
    ThisTable.Rows.Add(o.Prop1, o.Prop2, etc);
}

answered Sep 14 '11 at 19:58

RoccoC5

4,185
16
20

I am creating a memorystream object with the file that is uploaded from a FileUpload control. the MemoryStream "should" contain all the data – Kwalke001 Sep 14 '11 at 20:01
@Kwalke001 - The call to `bformat.Serialize(Mem, ThisTable)` is serializing the `ThisTable` object to your stream. If `ThisTable` contains no data at this point, it will contain no data when it is deserialized. – RoccoC5 Sep 14 '11 at 20:06

Retrieving DataTable from Memory Stream.

2 Answers2