Added new kb article gridview-snap-one-row-per-scroll

knowledge-base/gridview-snap-one-row-per-scroll.md

@@ -0,0 +1,78 @@
+---
+title: Forcing RadGridView to Snap One Row During Scrolling
+description: Learn how to force RadGridView in UI for WinForms to snap one row per scrolling, including mouse wheel scrolling.
+type: how-to
+page_title: Ensure RadGridView Scroll Rows One-by-One When Scrolling
+meta_title: Ensure RadGridView Scroll Rows One-by-One When Scrolling
+slug: gridview-snap-one-row-per-scroll
+tags: gridview, ui for winforms, scrolling, mousewheel, scrollmode, row-scrolling
+res_type: kb
+ticketid: 1702130
+---
+
+|Product Version|Product|Author|
+|----|----|----|
+|2025.3.812|RadGridView for WinForms|[Dinko Krastev](https://www.telerik.com/blogs/author/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](https://docs.telerik.com/devtools/winforms/controls/gridview/features/scrolling/scroll-modes) help article.
+
+````C#
+
+   this.radGridView1.TableElement.RowScroller.ScrollMode = ItemScrollerScrollModes.Discrete;
+
+````
+
+2. To apply the same behavior for mouse wheel scrolling, handle the `MouseWheel` event of RadGridView.
+
+````C#
+this.radGridView1.MouseWheel += RadGridView1_MouseWheel;
+
+````
+
+3. Implement the `RadGridView1_MouseWheel` event to calculate new scroll positions based on row height and wheel direction.
+
+````C#
+
+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](https://docs.telerik.com/devtools/winforms/controls/gridview/features/scrolling/scroll-modes)
+* [RadGridView Overview](https://docs.telerik.com/devtools/winforms/controls/gridview/overview)