Casting DataTable to typed when using DataTableExtensions.CopyToDataTable

[Andrew Jocelyn]

Hi

I have a LINQ query

var query = from t in TypedDataTable
select t

query contains Typed DataRows but I don't seem to be able to cast the
returned DataTable from the DataTableExtensions.CopyToDataTable:

DataSet.TypedTable tbl = (DataSet.TypedTable)query.CopyToDataTable();

What would be the best approach here?

Thanks
Andrew

 

[Marc Gravell]

There is an overload:

TypedTable table = new TypedTable();
query.CopyToDataTable(table, LoadOption.PreserveChanges);

your table should now contain the rows you want.

I haven't tested it (I'm not really a DataTable person...) but give it
a go ;-p

You could perhaps write a custom extension method, but I'm not sure it
would be worth it - since the table isn't an argument you end up
losing type inference...

Marc

 

[Linda Liu[MSFT]]

Hi Andrew,

The DataTableExtensions.CopyToDataTable method cannot return a strongly
typed DataTable.

To get what you want, we can define an instance of the strongly typed
DataTable and then call the Merge method to merge the returned DataTable
into the instance of the strongly typed DataTable.

For example:

var query = from t in TypedDataTable.AsEnumerable()
select t;
DataTable table = query.CopyToDataTable<TypedDataTableRow>();
TypedDataTable typedtable = new TypedDataTable();
typedtable.Merge(table);

Hope this helps.
If you have any question, please feel free to let me know.

Sincerely,
Linda Liu
Microsoft Online Community Support

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[Andrew Jocelyn]

Hi Linda

I was surprised that the CopyToDataTable method doesn't support Typed
DataTables but the Merge method does what I need.

Thanks
Andrew