Shortened syntax for Grid Column Definitions and Row Definitions with Public setter

src/Microsoft.DotNet.Wpf/cycle-breakers/PresentationFramework/PresentationFramework.cs

@@ -5036,6 +5036,24 @@ public void Refresh() { }
         public override bool ShouldSerializeContent() { throw null; }
         public void StopLoading() { }
     }
+    internal partial class ColumnDefinitionCollectionConverter : System.ComponentModel.TypeConverter
+    {
+        internal ColumnDefinitionCollectionConverter() { }
+        public override bool CanConvertFrom(System.ComponentModel.ITypeDescriptorContext typeDescriptorContext, System.Type sourceType) { throw null; }        
+        public override bool CanConvertTo(System.ComponentModel.ITypeDescriptorContext context, System.Type destinationType) { throw null; }
+        public override object ConvertFrom(System.ComponentModel.ITypeDescriptorContext typeDescriptorContext, System.Globalization.CultureInfo cultureInfo, object source) { throw null; }        
+        public override object ConvertTo(System.ComponentModel.ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, System.Type destinationType) { throw null; }
+    }
+
+    internal partial class RowDefinitionCollectionConverter : System.ComponentModel.TypeConverter
+    {
+        internal RowDefinitionCollectionConverter() { }
+        public override bool CanConvertFrom(System.ComponentModel.ITypeDescriptorContext typeDescriptorContext, System.Type sourceType) { throw null; }        
+        public override bool CanConvertTo(System.ComponentModel.ITypeDescriptorContext context, System.Type destinationType) { throw null; }
+        public override object ConvertFrom(System.ComponentModel.ITypeDescriptorContext typeDescriptorContext, System.Globalization.CultureInfo cultureInfo, object source) { throw null; }        
+        public override object ConvertTo(System.ComponentModel.ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, System.Type destinationType) { throw null; }
+    }
+
     public partial class Grid : System.Windows.Controls.Panel, System.Windows.Markup.IAddChild
     {
         public static readonly System.Windows.DependencyProperty ColumnProperty;
@@ -5045,9 +5063,11 @@ public partial class Grid : System.Windows.Controls.Panel, System.Windows.Markup
         public static readonly System.Windows.DependencyProperty RowSpanProperty;
         public static readonly System.Windows.DependencyProperty ShowGridLinesProperty;
         public Grid() { }
+        [System.ComponentModel.TypeConverterAttribute(typeof(System.Windows.Controls.ColumnDefinitionCollectionConverter))]
         [System.ComponentModel.DesignerSerializationVisibilityAttribute(System.ComponentModel.DesignerSerializationVisibility.Content)]
         public System.Windows.Controls.ColumnDefinitionCollection ColumnDefinitions { get { throw null; } }
         protected internal override System.Collections.IEnumerator LogicalChildren { get { throw null; } }
+        [System.ComponentModel.TypeConverterAttribute(typeof(System.Windows.Controls.RowDefinitionCollectionConverter))]
         [System.ComponentModel.DesignerSerializationVisibilityAttribute(System.ComponentModel.DesignerSerializationVisibility.Content)]
         public System.Windows.Controls.RowDefinitionCollection RowDefinitions { get { throw null; } }
         public bool ShowGridLines { get { throw null; } set { } }

src/Microsoft.DotNet.Wpf/src/PresentationFramework/PresentationFramework.csproj

@@ -547,6 +547,7 @@
     <Compile Include="System\Windows\Controls\CleanUpVirtualizedItemEventArgs.cs" />
     <Compile Include="System\Windows\Controls\ClickMode.cs" />
     <Compile Include="System\Windows\Controls\ColumnDefinition.cs" />
+    <Compile Include="System\Windows\Controls\ColumnDefinitionCollectionConverter.cs" />
     <Compile Include="System\Windows\Controls\ComboBox.cs" />
     <Compile Include="System\Windows\Controls\ComboBoxItem.cs" />
     <Compile Include="System\Windows\Controls\ContainerTracking.cs" />
@@ -739,6 +740,7 @@
     <Compile Include="System\Windows\Controls\RealizedColumnsBlock.cs" />
     <Compile Include="System\Windows\Controls\RichTextBox.cs" />
     <Compile Include="System\Windows\Controls\RowDefinition.cs" />
+    <Compile Include="System\Windows\Controls\RowDefinitionCollectionConverter.cs" />
     <Compile Include="System\Windows\Controls\ScrollChangedEventArgs.cs" />
     <Compile Include="System\Windows\Controls\ScrollUnit.cs" />
     <Compile Include="System\Windows\Controls\ScrollViewer.cs" />

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/ColumnDefinition.cs

@@ -562,7 +562,7 @@ private void PrivateValidateValueForAddition(object value)
                 throw new ArgumentException(SR.Format(SR.GridCollection_MustBeCertainType, "ColumnDefinitionCollection", "ColumnDefinition"));
             }
 
-            if (item.Parent != null)
+            if (item.Parent != _owner && item.Parent != null)
             {
                 throw new ArgumentException(SR.Format(SR.GridCollection_InOtherCollection, "value", "ColumnDefinitionCollection"));
             }

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/ColumnDefinitionCollectionConverter.cs

@@ -0,0 +1,115 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.ComponentModel;
+using System.Windows.Controls;
+using System.Windows.Markup;
+using System.Globalization;
+using MS.Internal;
+
+#pragma warning disable 1634, 1691  // suppressing PreSharp warnings
+
+namespace System.Windows.Controls
+{
+
+    internal class ColumnDefinitionCollectionConverter : TypeConverter
+    {
+        #region Public Methods
+
+        /// <summary>
+        /// CanConvertFrom - Returns whether or not this class can convert from a given type.
+        /// </summary>
+        /// <returns>
+        /// bool - True if thie converter can convert from the provided type, false if not.
+        /// </returns>
+        /// <param name="context"> The ITypeDescriptorContext for this call. </param>
+        /// <param name="sourceType"> The Type being queried for support. </param>
+        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
+        {
+            return sourceType == typeof(string) || base.CanConvertFrom(context, sourceType);
+        }
+
+        /// <summary>
+        /// CanConvertTo - Returns whether or not this class can convert to a given type.
+        /// </summary>
+        /// <returns>
+        /// bool - True if this converter can convert to the provided type, false if not.
+        /// </returns>
+        /// <param name="context"> The ITypeDescriptorContext for this call. </param>
+        /// <param name="destinationType"> The Type being queried for support. </param>
+        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
+        {
+            return destinationType == typeof(string) || base.CanConvertTo(context, destinationType);
+        }
+
+        /// <summary>
+        /// ConvertFrom - Attempt to convert to a ColumnDefinitionCollection from the given object.
+        /// </summary>
+        /// <returns>
+        /// The object which was constructoed.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// An ArgumentNullException is thrown if the example object is null.
+        /// </exception>
+        /// <param name="context"> The ITypeDescriptorContext for this call. </param>
+        /// <param name="culture"> The CultureInfo which is respected when converting. </param>
+        /// <param name="value"> The Thickness to convert. </param>
+        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
+        {
+            if(value != null && value is string input)
+            {
+                IProvideValueTarget ipvt = context?.GetService(typeof(IProvideValueTarget)) as IProvideValueTarget;
+                Grid grid = ipvt?.TargetObject as Grid;
+                if(grid != null)
+                {
+                    var collection = new ColumnDefinitionCollection(grid); // Pass Grid instance
+                    var converter = new GridLengthConverter();
+
+                    TokenizerHelper th = new TokenizerHelper(input, culture);
+                    while(th.NextToken())
+                    {
+                        collection.Add(new ColumnDefinition { Width = (GridLength)converter.ConvertFromString(th.GetCurrentToken()) });
+                    }
+
+                    return collection;
+                }
+            }
+            throw GetConvertFromException(value);
+        }
+
+        /// <summary>
+        /// ConvertTo - Attempt to convert a ColumnDefinitionCollection to the given type
+        /// </summary>
+        /// <returns>
+        /// The object which was constructoed.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// An ArgumentNullException is thrown if the example object is null.
+        /// </exception>
+        /// <param name="context"> The ITypeDescriptorContext for this call. </param>
+        /// <param name="culture"> The CultureInfo which is respected when converting. </param>
+        /// <param name="value"> The ColumnDefintionCollection to convert. </param>
+        /// <param name="destinationType">The type to which to convert the ColumnDefintionCollection instance. </param>
+        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
+        {
+            ArgumentNullException.ThrowIfNull(value);
+            ArgumentNullException.ThrowIfNull(destinationType);
+            if (destinationType == typeof(string) && value is ColumnDefinitionCollection columnDefinitions)
+            {
+                var parts = new string[columnDefinitions.Count];
+
+                for (int i = 0; i < columnDefinitions.Count; i++)
+                {
+                    parts[i] = columnDefinitions[i].Width.ToString();
+                }
+
+                return string.Join(",", parts);
+            }
+
+            return base.ConvertTo(context, culture, value, destinationType);
+        }
+
+        #endregion Public Methods
+    }
+}

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Grid.cs

@@ -31,7 +31,6 @@
 using System.Windows.Documents;
 using System.Windows.Media;
 using System.Windows.Markup;
-
 #pragma warning disable 1634, 1691  // suppressing PreSharp warnings
 
 namespace System.Windows.Controls
@@ -272,6 +271,7 @@ public bool ShowGridLines
         /// <summary>
         /// Returns a ColumnDefinitionCollection of column definitions.
         /// </summary>
+        [TypeConverter(typeof(ColumnDefinitionCollectionConverter))]
         [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
         public ColumnDefinitionCollection ColumnDefinitions
         {
@@ -282,11 +282,21 @@ public ColumnDefinitionCollection ColumnDefinitions
 
                 return (_data.ColumnDefinitions);
             }
+            set
+            {
+                if (value == null){
+                    _data.ColumnDefinitions = new ColumnDefinitionCollection(this);
+                    return;
+                }
+                _data ??= new ExtendedData();
+                _data.ColumnDefinitions = value;
+            }
         }
 
         /// <summary>
         /// Returns a RowDefinitionCollection of row definitions.
         /// </summary>
+        [TypeConverter(typeof(RowDefinitionCollectionConverter))]
         [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
         public RowDefinitionCollection RowDefinitions
         {
@@ -297,6 +307,15 @@ public RowDefinitionCollection RowDefinitions
 
                 return (_data.RowDefinitions);
             }
+            set
+            {
+                if (value == null){
+                     _data.RowDefinitions = new RowDefinitionCollection(this);
+                    return;
+                }
+                _data ??= new ExtendedData();
+                _data.RowDefinitions = value;
+            }
         }
 
         #endregion Public Properties

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/RowDefinition.cs

@@ -562,7 +562,7 @@ private void PrivateValidateValueForAddition(object value)
                 throw new ArgumentException(SR.Format(SR.GridCollection_MustBeCertainType, "RowDefinitionCollection", "RowDefinition"));
             }
 
-            if (item.Parent != null)
+            if (item.Parent != _owner && item.Parent != null)
             {
                 throw new ArgumentException(SR.Format(SR.GridCollection_InOtherCollection, "value", "RowDefinitionCollection"));
             }

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/RowDefinitionCollectionConverter.cs

@@ -0,0 +1,118 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.ComponentModel;
+using System.Windows.Controls;
+using System.Windows.Markup;
+using System.Globalization;
+using MS.Internal;
+
+#pragma warning disable 1634, 1691  // suppressing PreSharp warnings
+
+namespace System.Windows.Controls
+{
+
+    internal class RowDefinitionCollectionConverter : TypeConverter
+    {
+        #region Public Methods
+
+        /// <summary>
+        /// CanConvertFrom - Returns whether or not this class can convert from a given type.
+        /// </summary>
+        /// <returns>
+        /// bool - True if thie converter can convert from the provided type, false if not.
+        /// </returns>
+        /// <param name="context"> The ITypeDescriptorContext for this call. </param>
+        /// <param name="sourceType"> The Type being queried for support. </param>
+        public override bool CanConvertFrom(ITypeDescriptorContext context, Type sourceType)
+        {
+            return sourceType == typeof(string) || base.CanConvertFrom(context, sourceType);
+        }
+
+        /// <summary>
+        /// CanConvertTo - Returns whether or not this class can convert to a given type.
+        /// </summary>
+        /// <returns>
+        /// bool - True if this converter can convert to the provided type, false if not.
+        /// </returns>
+        /// <param name="context"> The ITypeDescriptorContext for this call. </param>
+        /// <param name="destinationType"> The Type being queried for support. </param>
+        public override bool CanConvertTo(ITypeDescriptorContext context, Type destinationType)
+        {
+            return destinationType == typeof(string) || base.CanConvertTo(context, destinationType);
+        }
+
+        /// <summary>
+        /// ConvertFrom - Attempt to convert to a RowDefinitionCollection from the given object.
+        /// </summary>
+        /// <returns>
+        /// The object which was constructoed.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// An ArgumentNullException is thrown if the example object is null.
+        /// </exception>
+        /// <exception cref="ArgumentException">
+        /// An ArgumentException is thrown if the object is not null and is not a valid type,
+        /// or if the destinationType isn't one of the valid destination types.
+        /// </exception>
+        /// <param name="context"> The ITypeDescriptorContext for this call. </param>
+        /// <param name="culture"> The CultureInfo which is respected when converting. </param>
+        /// <param name="value"> The Thickness to convert. </param>
+        public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
+        {
+            if(value != null && value is string input){
+                IProvideValueTarget ipvt = context?.GetService(typeof(IProvideValueTarget)) as IProvideValueTarget;
+                Grid grid = ipvt?.TargetObject as Grid;
+                if(grid != null)
+                {
+                    var collection = new RowDefinitionCollection(grid); // Pass Grid instance
+                    var converter = new GridLengthConverter();
+
+                    TokenizerHelper th = new TokenizerHelper(input, culture);
+                    while(th.NextToken())
+                    {
+                        collection.Add(new RowDefinition { Height = (GridLength)converter.ConvertFromString(th.GetCurrentToken()) });
+                    }
+
+                    return collection;
+                }
+            }            
+            throw GetConvertFromException(value);
+        }
+
+        /// <summary>
+        /// ConvertTo - Attempt to convert a RowDefinitionCollection to the given type
+        /// </summary>
+        /// <returns>
+        /// The object which was constructoed.
+        /// </returns>
+        /// <exception cref="ArgumentNullException">
+        /// An ArgumentNullException is thrown if the example object is null.
+        /// </exception>
+        /// <param name="context"> The ITypeDescriptorContext for this call. </param>
+        /// <param name="culture"> The CultureInfo which is respected when converting. </param>
+        /// <param name="value"> The RowDefintionCollection to convert. </param>
+        /// <param name="destinationType">The type to which to convert the RowDefintionCollection instance. </param>
+        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value, Type destinationType)
+        {
+            ArgumentNullException.ThrowIfNull(value);
+            ArgumentNullException.ThrowIfNull(destinationType);
+            if (destinationType == typeof(string) && value is RowDefinitionCollection RowDefinitions)
+            {
+                var parts = new string[RowDefinitions.Count];
+
+                for (int i = 0; i < RowDefinitions.Count; i++)
+                {
+                    parts[i] = RowDefinitions[i].Height.ToString();
+                }
+
+                return string.Join(",", parts);
+            }
+
+            return base.ConvertTo(context, culture, value, destinationType);
+        }
+
+        #endregion Public Methods
+    }
+}

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Markup/Baml2006/WpfGeneratedKnownProperties.cs

@@ -6403,7 +6403,9 @@ private WpfKnownMember Create_BamlProperty_Grid_ColumnDefinitions()
                             false // IsAttachable
                                      );
             bamlMember.GetDelegate = delegate(object target) { return ((System.Windows.Controls.Grid)target).ColumnDefinitions; };
+            bamlMember.SetDelegate = delegate(object target, object value) { ((System.Windows.Controls.Grid)target).ColumnDefinitions = (System.Windows.Controls.ColumnDefinitionCollection)value; };
             bamlMember.IsWritePrivate = true;
+            bamlMember.TypeConverterType = typeof(System.Windows.Controls.ColumnDefinitionCollectionConverter);
             bamlMember.Freeze();
             return bamlMember;
         }
@@ -6420,7 +6422,9 @@ private WpfKnownMember Create_BamlProperty_Grid_RowDefinitions()
                             false // IsAttachable
                                      );
             bamlMember.GetDelegate = delegate(object target) { return ((System.Windows.Controls.Grid)target).RowDefinitions; };
+            bamlMember.SetDelegate = delegate(object target, object value) { ((System.Windows.Controls.Grid)target).RowDefinitions = (System.Windows.Controls.RowDefinitionCollection)value; };
             bamlMember.IsWritePrivate = true;
+            bamlMember.TypeConverterType = typeof(System.Windows.Controls.RowDefinitionCollectionConverter);
             bamlMember.Freeze();
             return bamlMember;
         }