Select

I add a Button and put this code;
Dim aFind As String = InputBox("Enter a Employee No.", "Search for Employee No.")
Dim filteredRows() As DataRow = DataSet11.Employee.Select("empno='" & aFind & "'")

But it has no reaction. The DataGrid still show all the records.
What's wrong with this?

You have to add a clear statement first.
DataSet11.clear() 'Clear the dataset's data

and use the sql statement filter it out and fill it into the dataset

If you set the datasource of the datagrid to a DataView instead you can use the DataView.RowFilter property to filter your data.