Adds ValueFormatter to ProgressBar

src/Spectre.Console/Extensions/BarChartExtensions.cs

@@ -116,6 +116,43 @@ public static class BarChartExtensions
         return chart;
     }
 
+    /// <summary>
+    /// Sets the value formatter for the bar chart using culture info.
+    /// </summary>
+    /// <param name="chart">The bar chart.</param>
+    /// <param name="func">The value formatter function with culture info.</param>
+    /// <returns>The same instance so that multiple calls can be chained.</returns>
+    public static BarChart UseValueFormatter(this BarChart chart, Func<double, CultureInfo, string>? func)
+    {
+        if (chart is null)
+        {
+            throw new ArgumentNullException(nameof(chart));
+        }
+
+        chart.ValueFormatter = func;
+        return chart;
+    }
+
+    /// <summary>
+    /// Sets the value formatter for the bar chart.
+    /// </summary>
+    /// <param name="chart">The bar chart.</param>
+    /// <param name="func">The value formatter to use.</param>
+    /// <returns>The same instance so that multiple calls can be chained.</returns>
+    public static BarChart UseValueFormatter(this BarChart chart, Func<double, string>? func)
+    {
+        if (chart is null)
+        {
+            throw new ArgumentNullException(nameof(chart));
+        }
+
+        chart.ValueFormatter = func != null
+            ? (value, _) => func(value)
+            : null;
+
+        return chart;
+    }
+
     /// <summary>
     /// Sets the width of the bar chart.
     /// </summary>

src/Spectre.Console/Widgets/Charts/BarChart.cs

@@ -43,6 +43,11 @@ public sealed class BarChart : Renderable, IHasCulture
     /// <remarks>Defaults to null, which corresponds to largest value in chart.</remarks>
     public double? MaxValue { get; set; }
 
+    /// <summary>
+    /// Gets or sets the function used to format the values of the bar chart.
+    /// </summary>
+    public Func<double, CultureInfo, string>? ValueFormatter { get; set; }
+
     /// <summary>
     /// Initializes a new instance of the <see cref="BarChart"/> class.
     /// </summary>
@@ -90,6 +95,7 @@ public sealed class BarChart : Renderable, IHasCulture
                     AsciiBar = '█',
                     ShowValue = ShowValues,
                     Culture = Culture,
+                    ValueFormatter = ValueFormatter,
                 });
         }
 

src/Spectre.Console/Widgets/ProgressBar.cs

@@ -15,6 +15,7 @@ internal sealed class ProgressBar : Renderable, IHasCulture
     public bool ShowValue { get; set; }
     public bool IsIndeterminate { get; set; }
     public CultureInfo? Culture { get; set; }
+    public Func<double, CultureInfo, string>? ValueFormatter { get; set; }
 
     public Style CompletedStyle { get; set; } = Color.Yellow;
     public Style FinishedStyle { get; set; } = Color.Green;
@@ -50,7 +51,7 @@ internal sealed class ProgressBar : Renderable, IHasCulture
         var barCount = Math.Max(0, (int)(width * (completedBarCount / MaxValue)));
 
         // Show value?
-        var value = completedBarCount.ToString(Culture ?? CultureInfo.InvariantCulture);
+        var value = ValueFormatter != null ? ValueFormatter(completedBarCount, Culture ?? CultureInfo.InvariantCulture) : completedBarCount.ToString(Culture ?? CultureInfo.InvariantCulture);
         if (ShowValue)
         {
             barCount = barCount - value.Length - 1;