There is this DataView method called ToTable with two parameters: (and a three-parameter overloaded version)
a boolean param distinct
If true, the returned System.Data.DataTable contains rows that have distinct values for all its columns. The default value is false.
a string array param columnNames
A string array that contains a list of the column names to be included in the returned System.Data.DataTable. The System.Data.DataTable contains the specified columns in the order they appear within this array.
// create a dv from the source dt
DataView dv = new DataView(dt);
// set the output columns array of the destination dt
string[] strColumns = {"NodeID", "Title", "Url"};
// true = yes, i need distinct values.
dt = dv.ToTable(true, strColumns);
reference :
Remove Duplicate Records in a DataTable the Easy Way