Add design time converters

src/Controls/src/Core.Design/AttributeTableBuilder.cs

@@ -43,8 +43,7 @@ public AttributeTableBuilder()
 			   new TypeConverterAttribute(typeof(ItemsLayoutDesignTypeConverter)));
 
 			AddMemberAttributes("Microsoft.Maui.Controls.InputView", "Keyboard",
-			   new TypeConverterAttribute(typeof(KeyboardDesignTypeConverter)),
-			   new TypeConverterAttribute(typeof(StringConverter)));
+			   new TypeConverterAttribute(typeof(KeyboardDesignTypeConverter)));
 
 			AddMemberAttributes("Microsoft.Maui.Controls.EntryCell", "Keyboard",
 			   new TypeConverterAttribute(typeof(KeyboardDesignTypeConverter)));
@@ -67,37 +66,51 @@ public AttributeTableBuilder()
 			//new System.Windows.Markup.MarkupExtensionReturnTypeAttribute (),
 			);
 
+			// Type level attributes
 			AddTypeAttributes("Microsoft.Maui.Controls.Brush", new TypeConverterAttribute(typeof(ColorDesignTypeConverter)));
-			AddTypeAttributes("Microsoft.Maui.Graphics.Color", new TypeConverterAttribute(typeof(ColorDesignTypeConverter)));
-			AddTypeAttributes("Microsoft.Maui.GridLength", new TypeConverterAttribute(typeof(GridLengthDesignTypeConverter)));
-
+			AddTypeAttributes("Microsoft.Maui.Controls.Button+ButtonContentLayout", new TypeConverterAttribute(typeof(ButtonContentDesignTypeConverter)));
+			AddTypeAttributes("Microsoft.Maui.Controls.Compatibility.Constraint", new TypeConverterAttribute(typeof(ConstraintDesignTypeConverter)));
 			AddTypeAttributes("Microsoft.Maui.Controls.ConstraintExpression", new MarkupExtensionReturnTypeAttribute());
+			AddTypeAttributes("Microsoft.Maui.Controls.ImageSource", new TypeConverterAttribute(typeof(ImageSourceDesignTypeConverter)));
 			AddTypeAttributes("Microsoft.Maui.Controls.LayoutOptions", new TypeConverterAttribute(typeof(LayoutOptionsDesignTypeConverter)));
 			AddTypeAttributes("Microsoft.Maui.Controls.LinearItemsLayout", new TypeConverterAttribute(typeof(LinearItemsLayoutDesignTypeConverter)));
 			AddTypeAttributes("Microsoft.Maui.Controls.ResourcesChangedEventArgs", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
+			AddTypeAttributes("Microsoft.Maui.CornerRadius", new TypeConverterAttribute(typeof(CornerRadiusDesignTypeConverter)));
+			AddTypeAttributes("Microsoft.Maui.Graphics.Color", new TypeConverterAttribute(typeof(ColorDesignTypeConverter)));
+			AddTypeAttributes("Microsoft.Maui.Graphics.Point", new TypeConverterAttribute(typeof(PointTypeDesignConverter)));
+			AddTypeAttributes("Microsoft.Maui.Graphics.Rect", new TypeConverterAttribute(typeof(RectTypeDesignConverter)));
+			AddTypeAttributes("Microsoft.Maui.GridLength", new TypeConverterAttribute(typeof(GridLengthDesignTypeConverter)));
+			AddTypeAttributes("Microsoft.Maui.Layouts.FlexAlignContent", new TypeConverterAttribute(typeof(FlexAlignContentDesignTypeConverter)));
+			AddTypeAttributes("Microsoft.Maui.Layouts.FlexAlignItems", new TypeConverterAttribute(typeof(FlexAlignItemsDesignTypeConverter)));
+			AddTypeAttributes("Microsoft.Maui.Layouts.FlexAlignSelf", new TypeConverterAttribute(typeof(FlexAlignSelfDesignTypeConverter)));
+			AddTypeAttributes("Microsoft.Maui.Layouts.FlexBasis", new TypeConverterAttribute(typeof(FlexBasisDesignTypeConverter)));
+			AddTypeAttributes("Microsoft.Maui.Layouts.FlexDirection", new TypeConverterAttribute(typeof(FlexDirectionDesignTypeConverter)));
+			AddTypeAttributes("Microsoft.Maui.Layouts.FlexJustify", new TypeConverterAttribute(typeof(FlexJustifyDesignTypeConverter)));
+			AddTypeAttributes("Microsoft.Maui.Layouts.FlexWrap", new TypeConverterAttribute(typeof(FlexWrapDesignTypeConverter)));
+			AddTypeAttributes("Microsoft.Maui.Thickness", new TypeConverterAttribute(typeof(ThicknessTypeDesignConverter)));
 
+			// Property level attributes
+			AddMemberAttributes("Microsoft.Maui.Controls.AbsoluteLayout", "LayoutBounds", new TypeConverterAttribute(typeof(BoundsDesignTypeConverter)));
+			AddMemberAttributes("Microsoft.Maui.Controls.Button", "ContentLayout", new TypeConverterAttribute(typeof(ButtonContentDesignTypeConverter)));
 			AddMemberAttributes("Microsoft.Maui.Controls.Button", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
+			AddMemberAttributes("Microsoft.Maui.Controls.Compatibility.AbsoluteLayout", "LayoutBounds", new TypeConverterAttribute(typeof(BoundsDesignTypeConverter)));
 			AddMemberAttributes("Microsoft.Maui.Controls.DatePicker", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
 			AddMemberAttributes("Microsoft.Maui.Controls.Editor", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
 			AddMemberAttributes("Microsoft.Maui.Controls.Entry", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
+			AddMemberAttributes("Microsoft.Maui.Controls.Grid", "ColumnDefinitions", new TypeConverterAttribute(typeof(GridLengthCollectionDesignTypeConverter)));
+			AddMemberAttributes("Microsoft.Maui.Controls.Grid", "RowDefinitions", new TypeConverterAttribute(typeof(GridLengthCollectionDesignTypeConverter)));
+			AddMemberAttributes("Microsoft.Maui.Controls.Image", "Source", new TypeConverterAttribute(typeof(ImageSourceDesignTypeConverter)));
+			AddMemberAttributes("Microsoft.Maui.Controls.ImageButton", "Source", new TypeConverterAttribute(typeof(ImageSourceDesignTypeConverter)));
+			AddMemberAttributes("Microsoft.Maui.Controls.ImageCell", "ImageSource", new TypeConverterAttribute(typeof(ImageSourceDesignTypeConverter)));
 			AddMemberAttributes("Microsoft.Maui.Controls.Label", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
 			AddMemberAttributes("Microsoft.Maui.Controls.Picker", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
-			AddMemberAttributes("Microsoft.Maui.Controls.SearchBar", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
-			AddMemberAttributes("Microsoft.Maui.Controls.TimePicker", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
 			AddMemberAttributes("Microsoft.Maui.Controls.RadioButton", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
+			AddMemberAttributes("Microsoft.Maui.Controls.SearchBar", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
 			AddMemberAttributes("Microsoft.Maui.Controls.SearchHandler", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
+			AddMemberAttributes("Microsoft.Maui.Controls.Shell", "FlyoutBackgroundImage", new TypeConverterAttribute(typeof(ImageSourceDesignTypeConverter)));
 			AddMemberAttributes("Microsoft.Maui.Controls.Span", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
-
-			AddMemberAttributes("Microsoft.Maui.Controls.Grid", "RowDefinitions", new TypeConverterAttribute(typeof(GridLengthCollectionDesignTypeConverter)));
-			AddMemberAttributes("Microsoft.Maui.Controls.Grid", "ColumnDefinitions", new TypeConverterAttribute(typeof(GridLengthCollectionDesignTypeConverter)));
-
-			AddTypeAttributes("Microsoft.Maui.Layouts.FlexJustify", new TypeConverterAttribute(typeof(FlexJustifyDesignTypeConverter)));
-			AddTypeAttributes("Microsoft.Maui.Layouts.FlexDirection", new TypeConverterAttribute(typeof(FlexDirectionDesignTypeConverter)));
-			AddTypeAttributes("Microsoft.Maui.Layouts.FlexAlignContent", new TypeConverterAttribute(typeof(FlexAlignContentDesignTypeConverter)));
-			AddTypeAttributes("Microsoft.Maui.Layouts.FlexAlignItems", new TypeConverterAttribute(typeof(FlexAlignItemsDesignTypeConverter)));
-			AddTypeAttributes("Microsoft.Maui.Layouts.FlexAlignSelf", new TypeConverterAttribute(typeof(FlexAlignSelfDesignTypeConverter)));
-			AddTypeAttributes("Microsoft.Maui.Layouts.FlexWrap", new TypeConverterAttribute(typeof(FlexWrapDesignTypeConverter)));
-			AddTypeAttributes("Microsoft.Maui.Layouts.FlexBasis", new TypeConverterAttribute(typeof(FlexBasisDesignTypeConverter)));
+			AddMemberAttributes("Microsoft.Maui.Controls.TimePicker", "FontSize", new TypeConverterAttribute(typeof(FontSizeDesignTypeConverter)));
+			AddMemberAttributes("Microsoft.Maui.Controls.VisualElement", "IsVisible", new TypeConverterAttribute(typeof(VisibilityDesignTypeConverter)));
 		}
 
 		private void AddTypeAttributes(string typeName, params Attribute[] attribs)

src/Controls/src/Core.Design/BoundsDesignTypeConverter.cs

@@ -0,0 +1,41 @@
+using System;
+using System.ComponentModel;
+using System.Globalization;
+
+namespace Microsoft.Maui.Controls.Design
+{
+	public class BoundsDesignTypeConverter : StringConverter
+	{
+		public override bool IsValid(ITypeDescriptorContext context, object value)
+		{
+			// MUST MATCH BoundsTypeConverter.ConvertFrom
+			string strValue = value?.ToString();
+			if (string.IsNullOrEmpty(strValue))
+				return false;
+
+			string[] xywh = strValue.Split(',');
+			bool hasX, hasY, hasW, hasH;
+
+			hasX = (xywh.Length == 2 || xywh.Length == 4) && double.TryParse(xywh[0], NumberStyles.Number, CultureInfo.InvariantCulture, out _);
+			hasY = (xywh.Length == 2 || xywh.Length == 4) && double.TryParse(xywh[1], NumberStyles.Number, CultureInfo.InvariantCulture, out _);
+			hasW = xywh.Length == 4 && double.TryParse(xywh[2], NumberStyles.Number, CultureInfo.InvariantCulture, out _);
+			hasH = xywh.Length == 4 && double.TryParse(xywh[3], NumberStyles.Number, CultureInfo.InvariantCulture, out _);
+			if (!hasW && xywh.Length == 4 && string.Compare("AutoSize", xywh[2].Trim(), StringComparison.OrdinalIgnoreCase) == 0)
+			{
+				hasW = true;
+			}
+
+			if (!hasH && xywh.Length == 4 && string.Compare("AutoSize", xywh[3].Trim(), StringComparison.OrdinalIgnoreCase) == 0)
+			{
+				hasH = true;
+			}
+
+			if (hasX && hasY && xywh.Length == 2)
+				return true;
+			if (hasX && hasY && hasW && hasH && xywh.Length == 4)
+				return true;
+
+			return false;
+		}
+	}
+}

src/Controls/src/Core.Design/ButtonContentDesignTypeConverter.cs

@@ -0,0 +1,49 @@
+using System;
+using System.ComponentModel;
+
+namespace Microsoft.Maui.Controls.Design
+{
+	public class ButtonContentDesignTypeConverter : StringConverter
+	{
+		private static readonly char[] Separators = { ',' };
+
+		// MUST MATCH values of ButtonContentConverter.ImagePosition. NOTE that we use enum rather than strings
+		// to better match ButtonContentConverter. First, Enum.Parse will accept int values like 1 or 20. Second,
+		// values passed to converter contain numbers and enum values, i.e. there is a possibility that we might
+		// need to handle ints in place of enums. ButtonContentConverter does not properly handle corner cases.
+		// For example, it does not trim incoming strings, so " 15" will be converted as
+		// ButtonContentLayout((ImagePorition)15, DefaultSpacing/*10*/)
+		private enum ImagePosition { Left, Top, Right, Bottom }; 
+
+		public override bool IsValid(ITypeDescriptorContext context, object value)
+		{
+			// MUST MATCH ButtonContentConverter.ConvertFrom
+			string stringValue = value?.ToString();
+			if (string.IsNullOrEmpty(stringValue))
+				return false;
+
+			string[] parts = stringValue.Split(Separators, StringSplitOptions.RemoveEmptyEntries);
+			if (parts.Length > 2)
+				return false;
+
+			if (char.IsDigit(parts[0][0]))
+			{
+				// Examples: "5" or "10, Top"
+				if (!double.TryParse(parts[0], out _))
+					return false; // bogus number, e.g. 5a
+				if (parts.Length == 2 && !Enum.TryParse(parts[1], true, out ImagePosition _))
+					return false; // bogus position, e.g. "Hello"
+			}
+			else
+			{
+				// Examples: "Right" or "Bottom, 5"
+				if (!Enum.TryParse(parts[0], true, out ImagePosition _))
+					return false; // bogus position, e.g. "Hello"
+				if (parts.Length == 2 && !double.TryParse(parts[1], out _))
+					return false; // bogus number, e.g. 5a
+			}
+
+			return true;
+		}
+	}
+}

src/Controls/src/Core.Design/ConstraintDesignTypeConverter.cs

@@ -0,0 +1,15 @@
+using System.ComponentModel;
+using System.Globalization;
+
+namespace Microsoft.Maui.Controls.Design
+{
+	public class ConstraintDesignTypeConverter : StringConverter
+	{
+		public override bool IsValid(ITypeDescriptorContext context, object value)
+		{
+			// MUST MATCH ConstraintTypeConverter.ConvertFrom
+			var strValue = value?.ToString();
+			return (strValue != null && double.TryParse(strValue, NumberStyles.Number, CultureInfo.InvariantCulture, out _));
+		}
+	}
+}

src/Controls/src/Core.Design/Controls.Core.Design.csproj

@@ -8,25 +8,37 @@
 		<_MauiDesignDllBuild Condition=" '$(OS)' != 'Unix' ">True</_MauiDesignDllBuild>
 	</PropertyGroup>
 	<ItemGroup Condition=" '$(_MauiDesignDllBuild)' == 'True' ">
-		<Reference Include="System.Xaml" />
-		<Compile Include="AttributeTableBuilder.cs" />
-		<Compile Include="ColorDesignTypeConverter.cs" />
-		<Compile Include="EnumConverter.cs" />
-		<Compile Include="NonExclusiveEnumConverter.cs" />
-		<Compile Include="Properties\AssemblyInfo.cs" />
-		<Compile Include="RegisterMetadata.cs" />
-		<Compile Include="VisualDesignTypeConverter.cs" />
-		<Compile Include="ItemsLayoutDesignTypeConverter.cs" />
-		<Compile Include="KeyboardDesignTypeConverter.cs" />
-		<Compile Include="EasingDesignTypeConverter.cs" />
-		<Compile Include="FlowDirectionDesignTypeConverter.cs" />
-		<Compile Include="GridLengthCollectionDesignTypeConverter.cs" />
-		<Compile Include="GridLengthDesignTypeConverter.cs" />
-		<Compile Include="KnownValuesDesignTypeConverter.cs" />
-		<Compile Include="LayoutOptionsDesignTypeConverter.cs" />
-		<Compile Include="LinearItemsLayoutDesignTypeConverter.cs" />
-		<Compile Include="FontSizeDesignTypeConverter.cs" />
-		<Compile Include="FlexEnumDesignTypeConverters.cs" />
+    <Compile Include="AttributeTableBuilder.cs" />
+    <Compile Include="BoundsDesignTypeConverter.cs" />
+    <Compile Include="ButtonContentDesignTypeConverter.cs" />
+    <Compile Include="ColorDesignTypeConverter.cs" />
+    <Compile Include="ConstraintDesignTypeConverter.cs" />
+    <Compile Include="CornerRadiusDesignTypeConverter.cs" />
+    <Compile Include="DesignTypeConverterHelper.cs" />
+    <Compile Include="EasingDesignTypeConverter.cs" />
+    <Compile Include="EnumConverter.cs" />
+    <Compile Include="FlexEnumDesignTypeConverters.cs" />
+    <Compile Include="FlowDirectionDesignTypeConverter.cs" />
+    <Compile Include="FontSizeDesignTypeConverter.cs" />
+    <Compile Include="GridLengthCollectionDesignTypeConverter.cs" />
+    <Compile Include="GridLengthDesignTypeConverter.cs" />
+    <Compile Include="ImageSourceDesignTypeConverter.cs" />
+    <Compile Include="ItemsLayoutDesignTypeConverter.cs" />
+    <Compile Include="KeyboardDesignTypeConverter.cs" />
+    <Compile Include="KnownValuesDesignTypeConverter.cs" />
+    <Compile Include="LayoutOptionsDesignTypeConverter.cs" />
+    <Compile Include="LinearItemsLayoutDesignTypeConverter.cs" />
+    <Compile Include="NonExclusiveEnumConverter.cs" />
+    <Compile Include="PointTypeDesignConverter.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="RectTypeDesignConverter.cs" />
+    <Compile Include="RegisterMetadata.cs" />
+    <Compile Include="ThicknessTypeDesignConverter.cs" />
+    <Compile Include="VisibilityDesignTypeConverter.cs" />
+    <Compile Include="VisualDesignTypeConverter.cs" />
+    <Reference Include="System.Xaml" />
+	</ItemGroup>
+	<ItemGroup>
 		<PackageReference Include="Microsoft.VisualStudio.DesignTools.Extensibility" Version="17.5.33428.366" />
 	</ItemGroup>
 	<!-- The IDE will look for a top level assembly resource called 'Microsoft.Maui.toolbox.xml' to -->

src/Controls/src/Core.Design/CornerRadiusDesignTypeConverter.cs

@@ -0,0 +1,49 @@
+using System;
+using System.ComponentModel;
+using System.Globalization;
+using Controls.Core.Design;
+
+namespace Microsoft.Maui.Controls.Design
+{
+	public class CornerRadiusDesignTypeConverter : StringConverter
+	{
+		public override bool IsValid(ITypeDescriptorContext context, object value)
+		{
+			// MUST MATCH CornerRadiusTypeConverter.ConvertFrom
+			var strValue = value?.ToString();
+			if (strValue != null)
+			{
+				if (strValue.IndexOf(",", StringComparison.Ordinal) != -1)
+				{
+					var parts = strValue.Split(',');
+
+					// Example: "1,2,3,4"
+					if (parts.Length == 4)
+					{
+						foreach (string part in parts)
+						{
+							if (!double.TryParse(part, NumberStyles.Number, CultureInfo.InvariantCulture, out _))
+								return false;
+						}
+
+						return true;
+					}
+
+					// Example: "1,a,b". CornerRadiusTypeConverter has unusual behavior
+					// for 2 or 3 token string. We match its behavior here
+					if (parts.Length < 4)
+						return double.TryParse(parts[0], NumberStyles.Number, CultureInfo.InvariantCulture, out _);
+				}
+				else
+				{
+					// Example: "1 2 3 4". Any count of numbers between 1 and 4 is valid.
+					// Note that CornerRadiusTypeConverter is sensitive to spaces, e.g.
+					// "1 2" is valid but "1   2" is not. We match its behavior here.
+					return DesignTypeConverterHelper.TryParseNumbers(strValue.Trim(), ' ', maxCount: 4) is int;
+				}
+			}
+
+			return false;
+		}
+	}
+}

src/Controls/src/Core.Design/DesignTypeConverterHelper.cs

@@ -0,0 +1,28 @@
+using System.Globalization;
+
+namespace Controls.Core.Design
+{
+	internal static class DesignTypeConverterHelper
+	{
+		/// <summary>
+		/// Returns count of numbers in the string. Returns null if some of the values are invalid or total count exceeds max count.
+		/// </summary>
+		public static int? TryParseNumbers(string numberCollection, char separator, int maxCount)
+		{
+			// Examples: "1,2" or "1 2 3 4". 
+			if (string.IsNullOrEmpty(numberCollection))
+				return null;
+
+			string[] parts = numberCollection.Split(separator);
+			if (parts.Length > maxCount)
+				return null; // too many numbers
+
+			foreach (string part in parts)
+			{
+				if (!double.TryParse(part, NumberStyles.Number, CultureInfo.InvariantCulture, out _))
+					return null; // invalid number found
+			}
+			return parts.Length; // all numbers are valid
+		}
+	}
+}

src/Controls/src/Core.Design/ImageSourceDesignTypeConverter.cs

@@ -0,0 +1,17 @@
+using System;
+using System.ComponentModel;
+
+namespace Microsoft.Maui.Controls.Design
+{
+	public class ImageSourceDesignTypeConverter : StringConverter
+	{
+		public override bool IsValid(ITypeDescriptorContext context, object value)
+		{
+			// MUST MATCH ImageSourceConverter.ConvertFrom
+			if (value?.ToString() is string strValue)
+				return Uri.TryCreate(strValue, UriKind.Absolute, out Uri _);
+
+			return false;
+		}
+	}
+}

src/Controls/src/Core.Design/PointTypeDesignConverter.cs

@@ -0,0 +1,15 @@
+using System.ComponentModel;
+using Controls.Core.Design;
+
+namespace Microsoft.Maui.Controls.Design
+{
+	public class PointTypeDesignConverter : StringConverter
+	{
+		public override bool IsValid(ITypeDescriptorContext context, object value)
+		{
+			// MUST MATCH Point.TryParse
+			int? count = DesignTypeConverterHelper.TryParseNumbers(value?.ToString(), ',', 2);
+			return count == 2;
+		}
+	}
+}

src/Controls/src/Core.Design/RectTypeDesignConverter.cs

@@ -0,0 +1,15 @@
+using System.ComponentModel;
+using Controls.Core.Design;
+
+namespace Microsoft.Maui.Controls.Design
+{
+	public class RectTypeDesignConverter : StringConverter
+	{
+		public override bool IsValid(ITypeDescriptorContext context, object value)
+		{
+			// MUST MATCH Rect.TryParse
+			int? count = DesignTypeConverterHelper.TryParseNumbers(value?.ToString(), ',', 4);
+			return count == 4;
+		}
+	}
+}