工程招标投标制度:以下邦定为什么出错？ASP.NET

SqlDataAdapter sda = new SqlDataAdapter("Select * From MyTemp",scn);
DataSet ds = new DataSet();
sda.Fill(ds,"AA");
DataTable dt = ds.Tables["AA"];

DataTable dtn = new DataTable();
for(int i=0;i<dt.Columns.Count;i++)
{
DataColumn dc = new DataColumn();
dc.DataType = dt.Columns[i].GetType();
dc.ColumnName = dt.Columns[i].ColumnName + (i + 1).ToString();
dtn.Columns.Add(dc);
}

SqlCommand scmd = new SqlCommand("Select * From MyTemp",scn);
scn.Open();
SqlDataReader sdr = scmd.ExecuteReader();
while(sdr.Read())
{
DataRow dr = dtn.NewRow();
for(int i=0;i<dt.Columns.Count;i++)
{
dr[dt.Columns[i].ColumnName + (i + 1).ToString()] = sdr[dt.Columns[i].ColumnName];
}
dtn.Rows.Add(dr);
}
scn.Close();

DataGrid1.DataSource = dtn.DefaultView;
DataGrid1.DataBind();