Consider my datatable,
Id Name MobNo
1 ac 9566643707
2 bc 9944556612
3 cc 9566643707
How to remove the row 3 which contains duplicate MobNo column value in c# without using LINQ. I have seen similar questions on SO but all the answers uses LINQ.
The following method did what i want....
public DataTable RemoveDuplicateRows(DataTable dTable, string colName)
{
Hashtable hTable = new Hashtable();
ArrayList duplicateList = new ArrayList();
//Add list of all the unique item value to hashtable, which stores combination of key, value pair.
//And add duplicate item value in arraylist.
foreach (DataRow drow in dTable.Rows)
{
if (hTable.Contains(drow[colName]))
duplicateList.Add(drow);
else
hTable.Add(drow[colName], string.Empty);
}
//Removing a list of duplicate items from datatable.
foreach (DataRow dRow in duplicateList)
dTable.Rows.Remove(dRow);
//Datatable which contains unique records will be return as output.
return dTable;
}
As you are reading your CSV file ( a bit of pseudo code, but you get the picture ):
List<String> uniqueMobiles = new List<String>();
String[] fileLines = readYourFile();
for (String line in fileLines) {
DataRow row = parseLine(line);
if (uniqueMobiles.Contains(row["MobNum"])
{
continue;
}
uniqueMobiles.Add(row["MobNum"]);
yourDataTable.Rows.Add(row);
}
This will only load the records with unique mobiles into your data table.
This is the simplest way .
**
var uniqueContacts = dt.AsEnumerable()
.GroupBy(x=>x.Field<string>("Email"))
.Select(g=>g.First());
** I found it in this thread LINQ to remove duplicate rows from a datatable based on the value of a specific row
what actually was for me that I return it as datatable
DataTable uniqueContacts = dt.AsEnumerable()
.GroupBy(x=>x.Field<string>("Email"))
.Select(g=>g.First()).CopyToDataTable();
You might want to look up the inner workings on DISTINCT before running this on your sharp DB (be sure to back up!), but if it works as I think it does (grabbing the first value) you should be able to use (something very similar to) the following SQL:
DELETE FROM YourTable WHERE Id NOT IN (SELECT DISTINCT Id, MobNo FROM YourTable);
You can use "IEqualityComparer" in C#
