Basic support for DataContext={resource: ...}

src/AutoUI/Core/AutoUIContext.cs

@@ -13,6 +13,7 @@
 using DotVVM.Framework.Binding.Expressions;
 using DotVVM.Framework.Binding.Properties;
 using DotVVM.Framework.Compilation.ControlTree;
+using DotVVM.Framework.Utils;
 using DotVVM.Framework.ViewModel.Validation;
 using Microsoft.Extensions.DependencyInjection;
 
@@ -57,9 +58,8 @@ public ValidationAttribute[] GetPropertyValidators(PropertyDisplayMetadata prope
                 return Array.Empty<ValidationAttribute>();
             return GetPropertyValidators(property.PropertyInfo);
         }
-
 
-        public IValueBinding CreateValueBinding(PropertyDisplayMetadata property)
+        public IStaticValueBinding CreateValueBinding(PropertyDisplayMetadata property)
         {
             if (property.ValueBinding is not null)
                 return property.ValueBinding;
@@ -68,10 +68,12 @@ public IValueBinding CreateValueBinding(PropertyDisplayMetadata property)
                 throw new ArgumentException("property.PropertyInfo is null => cannot create value binding for this property");
 
             var s = this.BindingService;
-            return s.Cache.CreateCachedBinding("AutoUI-Value", new object?[] { property.PropertyInfo, DataContextStack }, () => {
+            var serverOnly = this.DataContextStack.ServerSideOnly;
+            return s.Cache.CreateCachedBinding("AutoUI-Value", new object?[] { BoxingUtils.Box(serverOnly), property.PropertyInfo, DataContextStack }, () => {
                 var _this = Expression.Parameter(DataContextStack.DataContextType, "_this").AddParameterAnnotation(new BindingParameterAnnotation(DataContextStack));
                 var expr = Expression.Property(_this, property.PropertyInfo);
-                return (IValueBinding)BindingService.CreateBinding(typeof(ValueBindingExpression<>), new object[] {
+                var bindingType = serverOnly ? typeof(ResourceBindingExpression<>) : typeof(ValueBindingExpression<>);
+                return (IStaticValueBinding)BindingService.CreateBinding(bindingType, new object[] {
                     DataContextStack,
                     new ParsedExpressionBindingProperty(expr)
                 });

src/AutoUI/Core/Controls/AutoEditor.cs

@@ -63,7 +63,7 @@ public sealed record Props
             /// <summary>
             /// Gets or sets the viewmodel property for which the editor should be generated.
             /// </summary>
-            public IValueBinding? Property { get; init; }
+            public IStaticValueBinding? Property { get; init; }
 
             /// <summary>
             /// Gets or sets the command that will be triggered when the value in the editor is changed.

src/AutoUI/Core/Controls/AutoGridViewColumn.cs

@@ -14,14 +14,14 @@ namespace DotVVM.AutoUI.Controls
     [ControlMarkupOptions(PrimaryName = "GridViewColumn")]
     public class AutoGridViewColumn : GridViewColumn
     {
-        [MarkupOptions(AllowHardCodedValue = false, Required = true)]
-        public IValueBinding? Property
+        [MarkupOptions(AllowHardCodedValue = false, AllowResourceBinding = true, Required = true)]
+        public IStaticValueBinding? Property
         {
-            get { return (IValueBinding?)GetValue(PropertyProperty); }
+            get { return (IStaticValueBinding?)GetValue(PropertyProperty); }
             set { SetValue(PropertyProperty, value); }
         }
         public static readonly DotvvmProperty PropertyProperty =
-            DotvvmProperty.Register<IValueBinding, AutoGridViewColumn>(nameof(Property));
+            DotvvmProperty.Register<IStaticValueBinding, AutoGridViewColumn>(nameof(Property));
 
 
         public static DotvvmCapabilityProperty PropsProperty =
@@ -93,7 +93,7 @@ private static GridViewColumn CreateColumn(AutoUIContext context, Props props, M
         [DotvvmControlCapability]
         public sealed record Props
         {
-            public IValueBinding? Property { get; init; }
+            public IStaticValueBinding? Property { get; init; }
             public ValueOrBinding<bool> IsEditable { get; init; } = new(true);
             public ValueOrBinding<string>? HeaderText { get; init; }
             public ITemplate? HeaderTemplate { get; init; }

src/AutoUI/Core/Controls/BootstrapForm.cs

@@ -121,7 +121,6 @@ public DotvvmControl GetContents(FieldProps props)
                 Label? labelElement;
                 HtmlGenericControl controlElement;
                 var formGroup = InitializeFormGroup(property, context, props, out labelElement, out controlElement);
-
 
                 // create the validator
                 InitializeValidation(controlElement, labelElement, property, context);

src/AutoUI/Core/Metadata/PropertyDisplayMetadata.cs

@@ -18,7 +18,7 @@ public record PropertyDisplayMetadata
         public string Name { get; init; }
         public Type Type { get; init; }
 
-        public IValueBinding? ValueBinding { get; init; }
+        public IStaticValueBinding? ValueBinding { get; init; }
 
         public LocalizableString? DisplayName { get; set; }
         public LocalizableString? Placeholder { get; set; }

src/AutoUI/Core/PropertyHandlers/FormEditors/EnumComboBoxFormEditorProvider.cs

@@ -42,7 +42,7 @@ public override DotvvmControl CreateControl(PropertyDisplayMetadata property, Au
                 .SetCapability(props.Html)
                 .SetProperty(c => c.Enabled, props.Enabled)
                 .SetProperty(c => c.SelectionChanged, props.Changed)
-                .SetProperty(c => c.SelectedValue, (IValueBinding)context.CreateValueBinding(property));
+                .SetProperty(c => c.SelectedValue, props.Property);
 
             if (isNullable)
             {

src/AutoUI/Core/PropertyHandlers/GridColumns/CheckBoxGridColumnProvider.cs

@@ -15,7 +15,7 @@ public override bool CanHandleProperty(PropertyDisplayMetadata property, AutoUIC
         protected override GridViewColumn CreateColumnCore(PropertyDisplayMetadata property, AutoGridViewColumn.Props props, AutoUIContext context)
         {
             var column = new GridViewCheckBoxColumn();
-            column.SetBinding(GridViewCheckBoxColumn.ValueBindingProperty, context.CreateValueBinding(property));
+            column.SetBinding(GridViewCheckBoxColumn.ValueBindingProperty, props.Property);
             return column;
         }
     }

src/DynamicData/DynamicData/DataContextStackHelper.cs

@@ -40,4 +40,4 @@ public static DataContextStack CreateChildStack(this DataContextStack dataContex
                 dataContextStack.BindingPropertyResolvers);
         }
     }
-}
+}

src/Framework/Core/Controls/GenericGridViewDataSet.cs

@@ -29,7 +29,7 @@ public class GenericGridViewDataSet<
         /// <summary>
         /// Gets or sets the items for the current page.
         /// </summary>
-        public IList<T> Items { get; set; } = new List<T>();
+        public virtual IList<T> Items { get; set; } = new List<T>();
 
         /// <summary>
         /// Gets or sets whether the data should be refreshed. This property is set to true automatically

src/Framework/Core/Controls/ServerSideGridViewDataSet.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using DotVVM.Framework.ViewModel;
+
+namespace DotVVM.Framework.Controls
+{
+    /// <summary>
+    /// Represents a collection of items with paging and sorting which keeps the Items collection server-side (Bind(Direction.None)) and only transfers the necessary metadata (page index, sort direction). 
+    /// </summary>
+    /// <typeparam name="T">The type of the elements in the collection.</typeparam>
+    public class ServerSideGridViewDataSet<T>()
+        : GenericGridViewDataSet<T, NoFilteringOptions, SortingOptions, PagingOptions, NoRowInsertOptions, NoRowEditOptions>(new(), new(), new(), new(), new())
+    {
+
+        [Bind(Direction.None)]
+        public override IList<T> Items { get => base.Items; set => base.Items = value; }
+        // return specialized dataset options
+        public new GridViewDataSetOptions GetOptions()
+        {
+            return new GridViewDataSetOptions {
+                FilteringOptions = FilteringOptions,
+                SortingOptions = SortingOptions,
+                PagingOptions = PagingOptions
+            };
+        }
+    }
+}

src/Framework/Framework/Binding/BindingHelper.cs

@@ -90,10 +90,29 @@ internal static (int stepsUp, DotvvmBindableObject target) FindDataContextTarget
             var changes = 0;
             foreach (var a in control.GetAllAncestors(includingThis: true))
             {
-                if (bindingContext.Equals(a.GetDataContextType(inherit: false)))
+                var ancestorContext = a.GetDataContextType(inherit: false);
+                if (bindingContext.Equals(ancestorContext))
                     return (changes, a);
 
-                if (a.properties.Contains(DotvvmBindableObject.DataContextProperty)) changes++;
+                // count only client-side data contexts (DataContext={resource:} is skipped in JS)
+                if (a.properties.TryGet(DotvvmBindableObject.DataContextProperty, out var ancestorRuntimeContext))
+                {
+                    if (a.properties.TryGet(Internal.IsServerOnlyDataContextProperty, out var isServerOnly) && isServerOnly != null)
+                    {
+                        if (isServerOnly is false)
+                            changes++;
+                    }
+                    else
+                    {
+                        // we only count bindings which are not value bindings as client-side
+                        // scalar values (null or otherwise) are used by Repeater to the collection elements
+                        // (since this logic got inlined into many other ItemsControls and is painful to debug, let's not change it)
+                        if (ancestorRuntimeContext is null ||
+                            ancestorRuntimeContext is IValueBinding ||
+                            ancestorRuntimeContext is not IBinding)
+                            changes++;
+                    }
+                }
             }
 
             // try to get the real objects, to see which is wrong
@@ -361,10 +380,12 @@ public static Func<TParam, TResult> Cache<TParam, TResult>(this Func<TParam, TRe
             return f => cache.GetOrAdd(f, func);
         }
 
-        public static IValueBinding GetThisBinding(this DotvvmBindableObject obj)
+        public static IStaticValueBinding GetThisBinding(this DotvvmBindableObject obj)
         {
-            var dataContext = obj.GetValueBinding(DotvvmBindableObject.DataContextProperty);
-            return (IValueBinding)dataContext!.GetProperty<ThisBindingProperty>().binding;
+            var dataContext = (IStaticValueBinding?)obj.GetBinding(DotvvmBindableObject.DataContextProperty);
+            if (dataContext is null)
+                throw new InvalidOperationException("DataContext must be set to a binding to allow creation of a {value: _this} binding");
+            return (IStaticValueBinding)dataContext!.GetProperty<ThisBindingProperty>().binding;
         }
 
         private static readonly ConditionalWeakTable<Expression, BindingParameterAnnotation> _expressionAnnotations =
@@ -403,7 +424,7 @@ public static TControl SetDataContextTypeFromDataSource<TControl>(this TControl
                 return dataContextType;
             }
 
-            var (childType, extensionParameters, addLayer) = ApplyDataContextChange(dataContextType, property.DataContextChangeAttributes, obj, property);
+            var (childType, extensionParameters, addLayer, serverOnly) = ApplyDataContextChange(dataContextType, property.DataContextChangeAttributes, obj, property);
 
             if (!addLayer)
             {
@@ -412,7 +433,7 @@ public static TControl SetDataContextTypeFromDataSource<TControl>(this TControl
             }
 
             if (childType is null) return null; // childType is null in case there is some error in processing (e.g. enumerable was expected).
-            else return DataContextStack.Create(childType, dataContextType, extensionParameters: extensionParameters.ToArray());
+            else return DataContextStack.Create(childType, dataContextType, extensionParameters: extensionParameters.ToArray(), serverSideOnly: serverOnly);
         }
 
         /// <summary> Return the expected data context type for this property. Returns null if the type is unknown. </summary>
@@ -432,7 +453,7 @@ public static DataContextStack GetDataContextType(this DotvvmProperty property,
                 return dataContextType;
             }
 
-            var (childType, extensionParameters, addLayer) = ApplyDataContextChange(dataContextType, property.DataContextChangeAttributes, obj, property);
+            var (childType, extensionParameters, addLayer, serverOnly) = ApplyDataContextChange(dataContextType, property.DataContextChangeAttributes, obj, property);
 
             if (!addLayer)
             {
@@ -443,14 +464,16 @@ public static DataContextStack GetDataContextType(this DotvvmProperty property,
             if (childType is null)
                 childType = typeof(UnknownTypeSentinel);
 
-            return DataContextStack.Create(childType, dataContextType, extensionParameters: extensionParameters.ToArray());
+            return DataContextStack.Create(childType, dataContextType, extensionParameters: extensionParameters.ToArray(), serverSideOnly: serverOnly);
         }
 
-        public static (Type? type, List<BindingExtensionParameter> extensionParameters, bool addLayer) ApplyDataContextChange(DataContextStack dataContext, DataContextChangeAttribute[] attributes, ResolvedControl control, DotvvmProperty? property)
+        public static (Type? type, List<BindingExtensionParameter> extensionParameters, bool addLayer, bool serverOnly) ApplyDataContextChange(DataContextStack dataContext, DataContextChangeAttribute[] attributes, ResolvedControl control, DotvvmProperty? property)
         {
             var type = ResolvedTypeDescriptor.Create(dataContext.DataContextType);
             var extensionParameters = new List<BindingExtensionParameter>();
             var addLayer = false;
+            var serverOnly = dataContext.ServerSideOnly;
+
             foreach (var attribute in attributes.OrderBy(a => a.Order))
             {
                 if (type == null) break;
@@ -459,17 +482,19 @@ public static (Type? type, List<BindingExtensionParameter> extensionParameters,
                 {
                     addLayer = true;
                     type = attribute.GetChildDataContextType(type, dataContext, control, property);
+                    serverOnly = attribute.IsServerSideOnly(dataContext, control, property) ?? serverOnly;
                 }
             }
-            return (ResolvedTypeDescriptor.ToSystemType(type), extensionParameters, addLayer);
+            return (ResolvedTypeDescriptor.ToSystemType(type), extensionParameters, addLayer, serverOnly);
         }
 
 
-        private static (Type? childType, List<BindingExtensionParameter> extensionParameters, bool addLayer) ApplyDataContextChange(DataContextStack dataContextType, DataContextChangeAttribute[] attributes, DotvvmBindableObject obj, DotvvmProperty property)
+        private static (Type? childType, List<BindingExtensionParameter> extensionParameters, bool addLayer, bool serverOnly) ApplyDataContextChange(DataContextStack dataContextType, DataContextChangeAttribute[] attributes, DotvvmBindableObject obj, DotvvmProperty property)
         {
             Type? type = dataContextType.DataContextType;
             var extensionParameters = new List<BindingExtensionParameter>();
             var addLayer = false;
+            var serverOnly = dataContextType.ServerSideOnly;
 
             foreach (var attribute in attributes.OrderBy(a => a.Order))
             {
@@ -479,10 +504,11 @@ private static (Type? childType, List<BindingExtensionParameter> extensionParame
                 {
                     addLayer = true;
                     type = attribute.GetChildDataContextType(type, dataContextType, obj, property);
+                    serverOnly = attribute.IsServerSideOnly(dataContextType, obj, property) ?? serverOnly;
                 }
             }
 
-            return (type, extensionParameters, addLayer);
+            return (type, extensionParameters, addLayer, serverOnly);
         }
 
         /// <summary>

src/Framework/Framework/Binding/BindingProperties.cs

@@ -234,5 +234,5 @@ public sealed record IsNullOrEmptyBindingExpression(IBinding Binding);
     /// <summary> Contains the same binding as this binding but converted to a string. </summary>
     public sealed record ExpectedAsStringBindingExpression(IBinding Binding);
     /// <summary> Contains references to the .NET properties referenced in the binding. MainProperty is the property on the root node (modulo conversions and simple expressions). </summary>
-    public sealed record ReferencedViewModelPropertiesBindingProperty(PropertyInfo? MainProperty, PropertyInfo[] OtherProperties, IValueBinding UnwrappedBindingExpression);
+    public sealed record ReferencedViewModelPropertiesBindingProperty(PropertyInfo? MainProperty, PropertyInfo[] OtherProperties, IValueBinding? UnwrappedBindingExpression);
 }

src/Framework/Framework/Binding/BindingPropertyException.cs

@@ -38,7 +38,7 @@ static string GetMessage(IBinding binding, Type[] properties, string? message, E
 
             var introMsg =
                 isRequiredProperty ?
-                $"Could not initialize binding as it is missing a required property {properties[0].Name}" :
+                $"Could not initialize binding '{binding}' as it is missing a required property {properties[0].Name}" :
                 $"Unable to get property {properties[0].Name}";
 
             var pathMsg = "";

src/Framework/Framework/Binding/ConstantDataContextChangeAttribute.cs

@@ -15,11 +15,13 @@ public class ConstantDataContextChangeAttribute : DataContextChangeAttribute
         public Type Type { get; }
 
         public override int Order { get; }
+        public bool? ServerSideOnly { get; }
 
-        public ConstantDataContextChangeAttribute(Type type, int order = 0)
+        public ConstantDataContextChangeAttribute(Type type, int order = 0, bool? serverSideOnly = null)
         {
             Type = type;
             Order = order;
+            ServerSideOnly = serverSideOnly;
         }
 
         public override ITypeDescriptor? GetChildDataContextType(ITypeDescriptor dataContext, IDataContextStack controlContextStack, IAbstractControl control, IPropertyDescriptor? property = null)
@@ -31,5 +33,10 @@ public ConstantDataContextChangeAttribute(Type type, int order = 0)
         {
             return Type;
         }
+
+        public override bool? IsServerSideOnly(IDataContextStack controlContextStack, IAbstractControl control, IPropertyDescriptor? property = null) =>
+            ServerSideOnly;
+        public override bool? IsServerSideOnly(DataContextStack controlContextStack, DotvvmBindableObject control, DotvvmProperty? property = null) =>
+            ServerSideOnly;
     }
 }