GetRowCount question

Question

Hello

I just found something here:

https://learn.microsoft.com/en-us/dotnet/desktop/winforms/controls/selection-modes-in-the-windows-forms-datagridview-control?view=netframeworkdesktop-4.8&source=recommendations

You can retrieve a collection of the currently selected cells, rows, or columns through the SelectedCells, SelectedRows, and SelectedColumns properties of the DataGridView control. Accessing these properties is inefficient when every cell in the control is selected. To avoid a performance penalty in this case, use the AreAllCellsSelected method first. Additionally, accessing these collections to determine the number of selected cells, rows, or columns can be inefficient. Instead, you should use the GetCellCount, GetRowCount, or GetColumnCount method, passing in the Selected value.

Well, does it mean I have to replace all of my:

DataGridView.Rows.Count

with:

DataGridView.Rows.GetRowCount(DataGridViewElementStates.Visible)

As well as:

DataGridView.SelectedRows.Count

with:

DataGridViewX.Rows.GetRowCount(DataGridViewElementStates.Selected)

When I need to get the number of rows and number of selected rows?

Thanks :)

Answer 1

Hi @StewartBW ,

You should replace DataGridView.SelectedRows.Count with DataGridView.Rows.GetRowCount(DataGridViewElementStates.Selected) when you need to get the number of selected rows, as the GetRowCount method is more efficient for this purpose.

However, for the total number of rows, you should not replace DataGridView.Rows.Count with DataGridView.Rows.GetRowCount(DataGridViewElementStates.Visible). The Rows.Count property already gives you the total number of rows, while GetRowCount(DataGridViewElementStates.Visible) will give you the count of rows that are currently visible.

Best Regards.

Jiachen Li

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