去除 DataTable中重复的Row

1. 使用 DataView

// 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); 

2. 使用linq groupby

protected DataTable Dedup(DataTable dt, params string [] keys)
{          
       DataTable result = null;
        switch(keys.Length)
       {
               case 1:
                     result = dt.AsEnumerable().GroupBy(row => new{ c0 = row[keys[0]] }).Select(g=>g.First()).CopyToDataTable();
                      break;               
               case 2:
                     result = dt.AsEnumerable().GroupBy(row => new{ c0 = row[keys[0]], c1 = row[keys[1]] }).Select(g=>g.First()).CopyToDataTable();
                      break;
               case 3:
                     result = dt.AsEnumerable().GroupBy(row => new{ c0 = row[keys[0]], c1 = row[keys[1]], c2=row[keys[2]] }).Select(g=>g.First()).CopyToDataTable();
                      break;        
       }
       
        return result;
}