Question

I have one problem in my application. I need to create two CSV files from the two SQL query results. I created that one. I’m using StreamWriter to write the data into the CSV files.

My problem is first query result also written into the second file. I used StreamWriter.Close() and am still seeing the same behavior in the output.

using (StreamWriter sw = new StreamWriter(strFilePath, false))
{
    foreach (DataRow dr in dt.Rows)
    {
        for (int i = 0; i < iColCount; i++)
        {
        }
     }
 }

Answer 1

The best way to ensure that a StreamWriter (or in fact, any IDisposable resource) is closed is to use the using statement where it is possible. Here is how:

using (var writer = new StreamWriter(@"c:\output\file1.csv")) {
    foreach (IDataReader row in myQueryResults) {
        writer.WriteLine("{0},{1},{2}", row.GetString(0), row.GetString(1), row.GetString(2));
    }
}

Once the scope of the using statement ends, normally or through an exception, the writer is closed automatically.