Best way to fill DataGridView with large amount of data

There are basically 3 ways to display data in a DataGridView

• Create the rows manually in a loop, as you are currently doing: as you have noticed, it's very inefficient if you have a lot of data

• Use the DataGridView's virtual mode, as suggested by Jonathan in his comment: the DGV only creates as many rows as can be displayed, and dynamically changes their contents when the user scrolls. You need to handle the CellValueNeeded event to provide the required data to the DGV

• Use databinding: that's by far the easiest way. You just fill a DataTable with the data from the database using a DbDataAdapter, and you assign this DataTable to the DGV's DataSource property. The DGV can automatically create the columns (AutoGenerateColumns = true), or you can create them manually (you must set the DataPropertyName of the column to the name of the field you want to display). In databound mode, the DGV works like in virtual mode except that it takes care of fetching the data from the datasource, so you don't have anything to do. It's very efficient even for a large number of rows

I think you can use DataReader method instead of DataAdapter. DataReader is very efficient oneway component, because it's only reading data from the source, and you can fill a data table with looping.

If you have a huge amount of rows, like 10 000 and more,

to avoid performance leak - do the following before data binding:

dataGridView1.RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.EnableResizing; 
//or even better .DisableResizing. 
//Most time consumption enum is DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders
dataGridView1.RowHeadersVisible = false; // set it to false if not needed

after data binding you may enable it.