Added new kb article gridview-sparkline-tooltip-text

Author: KB Bot

knowledge-base/gridview-sparkline-tooltip-text.md

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+---
+title: Setting ToolTip Text for GridViewSparklineColumn in RadGridView for WinForms
+description: Learn how to customize the ToolTip text for values displayed in the GridViewSparklineColumn in RadGridView for WinForms.
+type: how-to
+page_title: Customizing ToolTip Label for GridViewSparklineColumn in WinForms RadGridView
+slug: gridview-sparkline-tooltip-text
+tags: gridview, winforms, gridviewsparklinecolumn, tooltip, localizationprovider, tooltips, sparktooltipcontroller
+res_type: kb
+ticketid: 1681125
+---
+
+## Environment
+|Product Version|Product|Author|
+|----|----|----|
+|2025.1.211|RadGridView for WinForms|[Dinko Krastev](https://www.telerik.com/blogs/author/dinko-krastev)|
+
+## Description
+
+In the following tutorial, we will demonstrate how to add a ToolTip to the DataPoints inside the GridViewSparklineColumn. 
+
+## Solution
+
+To customize the ToolTip text for the GridViewSparklineColumn, handle the `DataPointTooltipTextNeeded` event of the `SparkTooltipController`. Access the controller by handling the `CellFormatting` event of the RadGridView. Below is the implementation:
+
+### Steps to Customize ToolTip Text
+
+1. Add a `GridViewSparklineColumn` to your RadGridView.
+2. Handle the `CellFormatting` event of the RadGridView to access the `SparkTooltipController`.
+3. Subscribe to the `DataPointTooltipTextNeeded` event of the `SparkTooltipController`.
+4. Customize the ToolTip text in the `DataPointTooltipTextNeeded` event based on your requirements.
+
+### Example Code
+
+````C#
+public partial class GridSparkForm : RadForm
+    {
+        public GridSparkForm()
+        {
+            InitializeComponent();
+
+            GridViewDecimalColumn idColumn = new GridViewDecimalColumn("Id");
+            this.radGridView1.Columns.Add(idColumn);
+
+            GridViewTextBoxColumn nameColumn = new GridViewTextBoxColumn("Name");
+            this.radGridView1.Columns.Add(nameColumn);
+
+            GridViewDateTimeColumn dateColumn = new GridViewDateTimeColumn("Date");
+            this.radGridView1.Columns.Add(dateColumn);
+
+            GridViewCheckBoxColumn boolColumn = new GridViewCheckBoxColumn("Bool");
+            this.radGridView1.Columns.Add(boolColumn);
+
+            GridViewSparklineColumn column = new GridViewSparklineColumn("SparkColumn") { Width = 400 };
+            column.SeriesType = SparkSeriesType.Line;
+            column.ShowMarkers = true;
+            column.ShowTooltip = true;
+            column.ShowHighPointIndicator = true;
+            column.ShowLowPointIndicator = true;
+            column.ShowNegativePointIndicators = true;
+            column.ShowFirstPointIndicator = true;
+            column.ShowLastPointIndicator = true;
+
+            column.SparkDataNeeded += this.Column_SparkDataNeeded;
+            this.radGridView1.DataSource = this.GetData();
+            this.radGridView1.Columns.Add(column);
+
+            this.radGridView1.CellFormatting += this.RadGridView1_CellFormatting;
+
+
+        }
+
+        private void RadGridView1_CellFormatting(object sender, CellFormattingEventArgs e)
+        {
+            var cell = e.CellElement as GridSparklineCellElement;
+            if (cell == null || cell.SparklineElement.View.Controllers.Count == 0)
+            {
+                return;
+            }
+
+            var controller = cell.SparklineElement.View.Controllers.Where(c => c is SparkTooltipController).First() as SparkTooltipController;
+            if (controller != null)
+            {
+                controller.DataPointTooltipTextNeeded -= Controller_DataPointTooltipTextNeeded;
+                controller.DataPointTooltipTextNeeded += Controller_DataPointTooltipTextNeeded;
+            }
+        }
+
+        private void Controller_DataPointTooltipTextNeeded(object sender, SparkDataPointTooltipTextNeededEventArgs e)
+        {
+            var point = e.DataPoint as CategoricalSparkDataPoint;
+            if (point.Value > 10)
+            {
+                e.Text = "Value Critical";
+            }
+        }
+
+        private void Column_SparkDataNeeded(object sender, SparkDataNeededEventArgs e)
+        {
+            GridSparklineCellElement cell = sender as GridSparklineCellElement;
+            if (cell == null)
+            {
+                return;
+            }
+
+            e.Cancel = true;
+            BindingList<ChartDataObject> data = new BindingList<ChartDataObject>();
+            for (int i = 1; i < 25; i++)
+            {
+                data.Add(new ChartDataObject
+                {
+                    //Value = i,
+                    Value = i % 2 == 0 ? i : -i,
+                    Category = DateTime.Now.AddDays(i)
+                });
+            }
+            
+            ((SparkCartesianSeries)cell.SparklineElement.Series).ValueMember = "Value";
+            ((SparkCartesianSeries)cell.SparklineElement.Series).CategoryMember = "Category";
+            cell.SparklineElement.Series.DataSource = data;
+        }
+
+        private DataTable GetData()
+        {
+            DataTable dt = new DataTable();
+
+            dt.Columns.Add("Id", typeof(int));
+            dt.Columns.Add("Name", typeof(string));
+            dt.Columns.Add("Date", typeof(DateTime));
+            dt.Columns.Add("Bool", typeof(bool));
+
+            Random rand = new Random();
+
+            for (int i = 0; i < 100; i++)
+            {
+                dt.Rows.Add(i, "Name " + i, DateTime.Now.AddDays(i), i % 2 == 0);
+            }
+
+            return dt;
+        }
+    }
+
+    public class ChartDataObject
+    {
+        public DateTime? Category { get; set; }
+
+        public double? Value { get; set; }
+    }
+
+````
+
+
+## See Also
+
+- [Sparkline Tooltips Documentation](https://docs.telerik.com/devtools/winforms/controls/sparkline/tooltips)
+- [RadGridView Documentation](https://docs.telerik.com/devtools/winforms/controls/gridview/overview)