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Hi experts,

I need your help in below regards. I have a table Name: "Persons", having multiple fields including ID, PersonID, Name etc.
To retrieve table data, I am firing "Select * from Persons" and setting values to dataset and binding it to Grid DataSource. Now I want to remove few PersonId from these list.
So for that I have created a list "listRecords" and adding those PersonID to this list. After that I have created a loop like below and removed items when PersonID matches. It's working fine but it's complexity is high, as I am creating a loop on List and then comparing to dataset table value.
I need your help to optimize it.
if (listRecords != null && listRecords.Count > 0)
                        foreach (string item in listRecords)
                            for (int i = 0; i < dataset.Tables[0].Rows.Count; i++)
                                if (item.Equals(dataset.Tables[0].Rows[i]["PersonID"], StringComparison.InvariantCultureIgnoreCase))

					grid.DataSource = dataset.Tables[0].DefaultView;


What I have tried:

Above mentioned code is working fine, which I have tried.
Updated 15-Aug-20 7:52am
[no name] 15-Aug-20 13:26pm    
How is about to fire an SQL DELETE FROM PERSONS WHERE PersonId = :PersonIdand afterwards refresh your SELECT *...?
User-8621695 15-Aug-20 13:30pm    
Thanks, but I don't have to make SQL call with delete operation,as I am doing few more operations on data and then removing it.
[no name] 15-Aug-20 14:03pm    
Sorry. I see now, I was completely wrong.

SELECT * FROM Persons WHERE PersonID NOT IN (... list of unwanted IDs ...)
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Dave Kreskowiak 15-Aug-20 13:51pm    
And get rid of the * in the SELECT.

Sorry, it's a pet peeve of mine.
OriginalGriff 15-Aug-20 13:57pm    
And mine - but I have no idea what the columns are.
First, as Griff says, do as much work within the database as you can.

Second, avoid foreach loop when a for loop will suffice.

Third, use the DataTable.DefaultView to filter (and sort) the rows in the table when you can.

Fourth, don't refer to columns by name within a loop -- use the ordinal.
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