Dataset rowfilter

Question

I have a dataset filled with names (1 table 1 collumn),
I then loop trough the dataset and add all of them as tree nodes to a treeview.

Then i want to aply a rowfilter after the rowfilter is set i want to loop trough the filtered set,
But evertime i do it nothing gets filtered it just displays everthing in the dataset.

I'm guessing that its my loop but im not sure:

for(int i=0; i < dataset_filter.Tables[0].Rows.Count; i++)

Rowfilter:

dataset_filter.Tables[0].DefaultView.RowFilter = "filter='" + filter.Text + "%'";

Thanks!