CODEWITHSUNDEEP
c#dataset
Simon
Simon

Reputation: 2035

DataSet hasChanges() always returns false

DataSet exportData = new DataSet();
SqlDataAdapter da = new SqlDataAdapter(getOutput);
da.Fill(exportData);
exportData.HasChanges()

ExportData.hasChanges() always returns false. Why? It should return true since it has a lot of new records inserted.

Upvotes: 1

Views: 3131

Answers (4)

Nikhil Agrawal
Nikhil Agrawal

Reputation: 48570

This value becomes true if you made changes to dataset and have not called "DataSet.AcceptChanges". In the meantime you can call RejectChanges to roll back to last time AcceptChanges were called.

Upvotes: 0

Sergey Kalinichenko
Sergey Kalinichenko

Reputation: 726909

You misunderstood the meaning of HasChanges. When you ask for HasChanges, you

Get a value indicating whether the DataSet has [your] changes, including new, deleted, or modified rows.

When you read from the DB, your data set is unchanged from the DB's perspective: it has exactly what's in the database, i.e. it is "clean". When you add, change, or remove data in the data set, the data set gets "dirty", so HasChanges starts returning true.

Upvotes: 1

D J
D J

Reputation: 7028

Try this using AcceptChangesDuringFill

 DataSet exportData = new DataSet();
 SqlDataAdapter da = new SqlDataAdapter(getOutput);
 da.AcceptChangesDuringFill = false;
 da.Fill(exportData);
 exportData.HasChanges();

Upvotes: 1

Tim Schmelter
Tim Schmelter

Reputation: 460238

Because the last what DataAdapter.Fill will do is to call AcceptChanges. You can change this behaviour with the AcceptChangesDuringFill property(default true).

In general the RowState is used to determine what to do with this record. If you add a new record to a DataTable, it's RowState will change to Added. Now a DataAdapter would know what to do when he should update this table.

But because actually you haven't added new records it would double all records if the default wouldn't be AcceptChangesDuringFill.

Upvotes: 2

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