How to convert DataSet to DataTable

Question

I am retrieving data from a SQL table so I can display the result on the page as a HTML table. Later I need to be able to save that table as a CSV file.

So far I have figured out how to retrieve the data and fill them in a dataset for display purpose (which is working perfectly)...

        string selectQuery = "SELECT Name, ProductNumber, ListPrice FROM Poduction.Product";

        // Establish the connection to the SQL database 
        SqlConnection conn = ConnectionManager.GetConnection();
        conn.Open();

        // Connect to the SQL database using the above query to get all the data from table.
        SqlDataAdapter myCommand = new SqlDataAdapter(selectQuery, conn);

        // Create and fill a DataSet.
        DataSet ds = new DataSet();
        myCommand.Fill(ds);

and how to save them in a CSV file with the help of following code from: http://www.evontech.com/login/topic/1983.html

    private void exportDataTableToCsv(DataTable formattedDataTable, string filename)
    {
       DataTable toExcel = formattedDataTable.Copy();
       HttpContext context = HttpContext.Current;
       context.Response.Clear();

       foreach (DataColumn column in toExcel.Columns)
       {
          context.Response.Write(column.ColumnName + ",");
       }

       context.Response.Write(Environment.NewLine);
       foreach (DataRow row in toExcel.Rows)
       {
          for (int i = 0; i < toExcel.Columns.Count; i++)
          {
             context.Response.Write(row.ToString().Replace(",", string.Empty) + ",");
          }

          context.Response.Write(Environment.NewLine);
       }

       context.Response.ContentType = "text/csv";
       context.Response.AppendHeader("Content-Disposition", "attachment; filename=" + filename + ".csv");
       context.Response.End();
    }

Now my problem is how do I convert this DataSet to DataTable? I have tried the way described here with NO luck: http://www.ezineasp.net/post/ASP-Net-C-sharp-Convert-DataSet-to-DataTable.aspx

Can anyone help me?

score 122 · Accepted Answer · answered Jan 24 '12 at 07:21

122

A DataSet already contains DataTables. You can just use:

DataTable firstTable = dataSet.Tables[0];

or by name:

DataTable customerTable = dataSet.Tables["Customer"];

Note that you should have using statements for your SQL code, to ensure the connection is disposed properly:

using (SqlConnection conn = ...)
{
    // Code here...
}

answered Jan 24 '12 at 07:21

Jon Skeet

1,421,763
867
9,128
9,194

1

Thanks for the quick responses! I have already tried this: mySqlAdapter.Fill(myDataSet); DataTable myDataTable = myDataSet.Tables[0]; but the CSV file does not look correct as the values are missing and replaced with "System.Data.DataRow".... Name,ProductNumber,ListPrice, System.Data.DataRow,System.Data.DataRow,System.Data.DataRow, System.Data.DataRow,System.Data.DataRow,System.Data.DataRow, System.Data.DataRow,System.Data.DataRow,System.Data.DataRow, System.Data.DataRow,System.Data.DataRow,System.Data.DataRow, how to fix this? – AlwaysANovice Jan 24 '12 at 07:54
1

@Walahh: Well your CSV code is calling `ToString()` on `DataRow`, which looks like a bad idea to me. I suggest you ask about that as a separate question, as it really isn't the same as the question you asked. – Jon Skeet Jan 24 '12 at 08:33
@JonSkeet - I am getting a DataSet from SSIS. I execute a SQL server query with ADO.NET connection. The result set is stored in a DataSet. Is there a way I could name my result set such that DataTable for it also gets the same name ? Otherwise, I can use the index. – Steam Dec 18 '13 at 05:43
I was wondering why could one need a collection of DataTables, ie DataSet to store the result sets of a query. A result set is always one table. So, what are the advantages of storing it in a DataSet instead ? – Steam Dec 18 '13 at 06:10
@blasto: You can issue a multi-result query, although I think it's relatively rare. To be honest I've never liked the "old-school" ADO.NET... – Jon Skeet Dec 18 '13 at 06:53
@JonSkeet - Oh yes. I now realized what you mean - the multiple select statements in Management Studio that show multiple result sets in the output/execution window. Makes sense now. I wonder why someone would want to do that. – Steam Dec 18 '13 at 07:09
@JonSkeet - Please tell me why you "never liked the "old-school" ADO.NET". I don't think I can use any other connection now. I dont want to use ADO or OLEDB. – Steam Dec 18 '13 at 07:10
@blasto: I've always preferred getting things into a strongly-typed form as quickly as possible. Strongly-typed datasets are better than nothing, but I still prefer a proper ORM. (I realize that comes with its own problems, of course...) – Jon Skeet Dec 18 '13 at 08:01
@Steam - Inside the dataset, you can have join logic similar to a database without having to send the data to the database after each incremental change (batch). This could be used to handle referential integrity like in a parent-child relationship. – JeffO Jul 02 '14 at 17:24

score 5 · Answer 2 · answered Jan 24 '12 at 07:22

5

DataSet is collection of DataTables.... you can get the datatable from DataSet as below.

//here ds is dataset
DatTable dt = ds.Table[0]; /// table of dataset

answered Jan 24 '12 at 07:22

Pranay Rana

175,020
35
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score 1 · Answer 3 · answered Mar 13 '17 at 19:04

1

Here is my solution:

DataTable datatable = (DataTable)dataset.datatablename;

answered Mar 13 '17 at 19:04

MORFEE89

137
4

How to convert DataSet to DataTable

3 Answers3

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