Datagrid to keep selected row and position after refresh

[amaru96]

Hi guys, I have a datagrid which starts off blank and slowly gets populated as processes execute. It also refreshes every 5 seconds using the timer.

The problem I have is, after it refreshes it resets the view to the top of the list. So you may have scrolled down and selected the 20th item in the list, but after the refresh it's back to the top.

I tried the below code but I get an error because the grid is empty to start with and it can't get the index location.

i = HistoryDataGridView.CurrentRow.Index
 HistoryDataGridView.CurrentCell = HistoryDataGridView.Rows(i).Cells(1)

Error I get is:
Additional information: Object reference not set to an instance of an object

Whats the best way to handle this?

One other question, how do I get the datagrid to retain it's current position? If for example I have scrolled down 40 rows, how do I get it stay there after the refresh?

[jmcilhinney]

What exactly is this "refresh" of which you speak? Do you mean that you remove all the rows and then repopulate the it? If so then there is no "staying" because if there are no rows in between then there can be no current row or scrolling position. You would need to remember the current row and scrolling position before removing all the rows, then reinstate them after the rows are re-added.

The code you have shown is correct in principle but the first line needs to be executed BEFORE removing all the rows and the second line AFTER re-adding them. You would need to do the same for the scrolling position, for which you would use the FirstDisplayedScrollingRowIndex property.

[amaru96]

By refresh I mean rebinding the datasource.

As for my problem, I managed to sort it out using a try catch (maybe not the best or most elegant, but does the job)

And for the scroll position I used the FirstDisplayedScrollingRowIndex as you suggested, Thanks.