Export Data To Excel Hindi From DataTable In Asp.net

Question

  I am using below code to export data to excel from datatable.But when i download it is showing ???.I had UTF8 encoding but it's not working.Can anyone help me out? 

public void ExportToExcel(DataTable dt)

{

Response.ClearContent();

Response.Buffer = true;

Response.AddHeader("content-disposition", string.Format("attachment; filename={0}", "Customers.xls"));

Response.ContentType = "application/ms-excel";

Response.ContentEncoding = System.Text.Encoding.UTF8;

Response.Charset = "";

DataTable dt1 = dt;

string str = string.Empty;

foreach (DataColumn dtcol in dt1.Columns)

{

Response.Write(str + dtcol.ColumnName);

str = "\t";

}

Response.Write("\n");

foreach (DataRow dr in dt1.Rows)

{

str = "";

for (int j = 0; j < dt1.Columns.Count; j++)

{

Response.Write(str + Convert.ToString(dr[j]));

str = "\t";

}

Response.Write("\n");

}

Response.End();

}