Forcing RadGridView to Snap One Row During Scrolling

Product Version	Product	Author
2025.3.812	RadGridView for WinForms	Dinko Krastev

Description

In this tutorial, we will demonstrate how to snap to row gridlines and display rows one by one during scrolling, especially when using the mouse wheel.

Solution

To achieve row-by-row scrolling in RadGridView, use discrete scrolling mode and add custom handling for mouse wheel scrolling.

1. Set the scrolling mode to discrete to enable row-by-row scrolling when using the scrollbar. This is further described in the Scroll Modes help article.

   this.radGridView1.TableElement.RowScroller.ScrollMode = ItemScrollerScrollModes.Discrete;

1. To apply the same behavior for mouse wheel scrolling, handle the MouseWheel event of RadGridView.

this.radGridView1.MouseWheel += RadGridView1_MouseWheel;

1. Implement the RadGridView1_MouseWheel event to calculate new scroll positions based on row height and wheel direction.

private void RadGridView1_MouseWheel(object sender, MouseEventArgs e)
{
    var grid = sender as RadGridView;
    if (grid == null || grid.RowCount == 0) return;

    // Positive delta = scroll up
    int direction = e.Delta > 0 ? -1 : 1;

    var vScrollBar = grid.TableElement.VScrollBar;

    // Scroll by one row at a time
    int newValue = vScrollBar.Value + (direction * grid.TableElement.RowHeight);
    newValue = Math.Max(vScrollBar.Minimum, Math.Min(vScrollBar.Maximum, newValue));

    if (direction == 1 && this.radGridView1.TableElement.VisualRows.Last().RowInfo == this.radGridView1.Rows.Last())
    {
        // hit last row
    }
    else
    {
        vScrollBar.Value = newValue;
    }            

    // Prevent default scrolling
    ((HandledMouseEventArgs)e).Handled = true;
}

This configuration ensures RadGridView scrolls one row at a time, maintaining alignment with gridlines for both scrollbar and mouse wheel interactions.

See Also

• Scroll Modes Documentation
• RadGridView Overview