Writing gridview to file does not work with nested for loop

string filename = @"C:Usersgurdip.siraDocumentsVisual Studio 2008WebSitesSupressionsAPP_DATAsurpressionstest.csv";
StreamWriter sWriter = new StreamWriter(filename);
string Str = string.Empty;

string headertext = "";

sWriter.WriteLine(headertext);

for (int i = 0; i <= (this.GridView3.Rows.Count - 1); i++)
{
    for (int j = 0; j <= (this.GridView3.Columns.Count - 1); j++)
    {
        Str = this.GridView3.Rows[i].Cells[j].Text.ToString();
        sWriter.Write(Str);
    }

sWriter.WriteLine();

}

sWriter.Close();

for (int i = 0; i <= (this.GridView3.Rows.Count - 1); i++)
    {

        for (int j = 0; j <= (this.GridView3.Rows[i].Cells.Count - 1); j++)
        {

            Str = this.GridView3.Rows[i].Cells[j].Text.ToString();


            sWriter.Write(Str);
        }
    }

string filename = @"C:Usersgurdip.siraDocumentsVisual Studio 2008WebSitesSupressionsAPP_DATAsurpressionstest.csv";//1
     StreamWriter sWriter = new StreamWriter(filename);//2
     string Str = string.Empty;//3
     string headertext = ""; //4
     sWriter.WriteLine(headertext);  //5
     for (int i = 0; i <= (this.GridView3.Rows.Count - 1); i++)   //6
     {         //7
        for (int j = 0; j <= (this.GridView3.Columns.Count - 1); j++)  //8
        { //9
               Str = this.GridView3.Rows[i].Cells[j].Text.ToString();//10
               sWriter.Write(Str);//11
        }//12
        sWriter.WriteLine();//13
      }//14
      sWriter.Close();//15
}//16