I have a Datatable with Id(guid) and Name(string) columns. I traverse through the data table and run a validation criteria on the Name (say, It should contain only letters and numbers) and then adding the corresponding Id to a List If name passes the validation.

Something like below:-

List<Guid> validIds=new List<Guid>();
foreach(DataRow row in DataTable1.Rows)
{
      if(IsValid(row["Name"])
        {
            validIds.Add((Guid)row["Id"]);
        }

}

In addition to this validation I should also check If the name is not repeating in the whole datatable (even for the case-sensitiveness), If It is repeating, I should not add the corresponding Id in the List.

Things I am thinking/have thought about:-

1) I can have another List, check for the "Name" in the same, If It exists, will add the corresponding Guild 2) I cannot use HashSet as that would treat "Test" and "test" as different strings and not duplicates. 3) Take the DataTable to another one where I have the disctict names (this I havent tried and the code might be incorrect, please correct me whereever possible)

DataTable dataTableWithDistinctName = new DataTable();
dataTableWithDistinctName.CaseSensitive=true
CopiedDataTable=DataTable1.DefaultView.ToTable(true,"Name");

I would loop through the original datatable and check the existence of the "Name" in the CopiedDataTable, If It exists, I wont add the Id to the List.

Are there any better and optimum way to achieve the same? I need to always think of performance. Although there are many related questions in SO, I didnt find a problem similar to this. If you could point me to a question similar to this, It would be helpful.

Thanks