Remove exceptions in ColorPicker converters and use UnsetValue

Author: robloo

Microsoft.Toolkit.Uwp.UI.Controls.Input/ColorPicker/ColorToColorShadeConverter.cs

@@ -5,6 +5,7 @@
 using System;
 using Microsoft.Toolkit.Uwp.Helpers;
 using Windows.UI;
+using Windows.UI.Xaml;
 using Windows.UI.Xaml.Data;
 using Windows.UI.Xaml.Media;
 
@@ -40,7 +41,8 @@ public object Convert(
             }
             else
             {
-                throw new ArgumentException("Invalid color value provided");
+                // Invalid color value provided
+                return DependencyProperty.UnsetValue;
             }
 
             // Get the value component delta
@@ -50,7 +52,8 @@ public object Convert(
             }
             catch
             {
-                throw new ArgumentException("Invalid parameter provided, unable to convert to integer");
+                // Invalid parameter provided, unable to convert to integer
+                return DependencyProperty.UnsetValue;
             }
 
             // Specially handle minimum (black) and maximum (white)
@@ -119,7 +122,7 @@ public object ConvertBack(
             object parameter,
             string language)
         {
-            throw new NotImplementedException();
+            return DependencyProperty.UnsetValue;
         }
     }
 }

Microsoft.Toolkit.Uwp.UI.Controls.Input/ColorPicker/ColorToHexConverter.cs

@@ -5,6 +5,7 @@
 using System;
 using Microsoft.Toolkit.Uwp.Helpers;
 using Windows.UI;
+using Windows.UI.Xaml;
 using Windows.UI.Xaml.Data;
 using Windows.UI.Xaml.Media;
 
@@ -34,7 +35,8 @@ public object Convert(
             }
             else
             {
-                throw new ArgumentException("Invalid color value provided");
+                // Invalid color value provided
+                return DependencyProperty.UnsetValue;
             }
 
             string hexColor = color.ToHex().Replace("#", string.Empty);
@@ -58,7 +60,8 @@ public object ConvertBack(
                 }
                 catch
                 {
-                    throw new ArgumentException("Invalid hex color value provided");
+                    // Invalid hex color value provided
+                    return DependencyProperty.UnsetValue;
                 }
             }
             else
@@ -69,7 +72,8 @@ public object ConvertBack(
                 }
                 catch
                 {
-                    throw new ArgumentException("Invalid hex color value provided");
+                    // Invalid hex color value provided
+                    return DependencyProperty.UnsetValue;
                 }
             }
         }

Microsoft.Toolkit.Uwp.UI.Controls.Input/ColorPicker/ContrastBrushConverter.cs

@@ -4,6 +4,7 @@
 
 using System;
 using Windows.UI;
+using Windows.UI.Xaml;
 using Windows.UI.Xaml.Data;
 using Windows.UI.Xaml.Media;
 
@@ -40,7 +41,8 @@ public object Convert(
             }
             else
             {
-                throw new ArgumentException("Invalid color value provided");
+                // Invalid color value provided
+                return DependencyProperty.UnsetValue;
             }
 
             // Get the default color when transparency is high
@@ -81,7 +83,7 @@ public object ConvertBack(
             object parameter,
             string language)
         {
-            throw new NotImplementedException();
+            return DependencyProperty.UnsetValue;
         }
 
         /// <summary>

Microsoft.Toolkit.Uwp.UI/Converters/ColorToDisplayNameConverter.cs

@@ -4,6 +4,7 @@
 
 using System;
 using Windows.UI;
+using Windows.UI.Xaml;
 using Windows.UI.Xaml.Data;
 using Windows.UI.Xaml.Media;
 
@@ -33,7 +34,8 @@ public object Convert(
             }
             else
             {
-                throw new ArgumentException("Invalid color value provided");
+                // Invalid color value provided
+                return DependencyProperty.UnsetValue;
             }
 
             return ColorHelper.ToDisplayName(color);
@@ -46,7 +48,7 @@ public object ConvertBack(
             object parameter,
             string language)
         {
-            throw new NotImplementedException();
+            return DependencyProperty.UnsetValue;
         }
     }
 }