Question

DataSet ds = DAL.GetData();
DataSet dsInvitee = null;

DataTable dt = ds.Tables[0].Copy();
IEnumerable<DataRow> q1 = dt.AsEnumerable().Skip(5).Take(10);

dsInvitee = new DataSet();

DataTable dtNew = new DataTable();
dtNew.TableName = "DTInv";
dtNew = q1.CopyToDataTable<DataRow>();
dsInvitee.Tables.Add(dtNew.Copy());
dsInvitee.AcceptChanges();

dtNew = null;
dtNew = new DataTable();
dtNew.TableName = "DTTags";
dtNew = ds.Tables[1].Copy();
dsInvitee.Tables.Add(dtNew.Copy());

I am getting error in the last line as “A DataTable named ‘Table1’ already belongs to this DataSet.”… Please help.

Answer 1

Your issue is because of the line dtNew = q1.CopyToDataTable<DataRow>();, because the CopyToDataTable extension method:

Returns a DataTable that contains copies of the DataRow objects, given an input IEnumerable object where the generic parameter T is DataRow.

This means that the table name of “DTInv” gets blown away as after the call to CopyToDataTable, dtNew no longer refers to the same DataTable. Move the dtNew.TableName = "DTInv"; to after the call to CopyToDataTable:

DataTable dtNew = new DataTable();
dtNew = q1.CopyToDataTable<DataRow>();
dtNew.TableName = "DTInv";
dsInvitee.Tables.Add(dtNew.Copy());
dsInvitee.AcceptChanges();