Repeater: Support for DataSource={resource: ...}

exyi · exyi · commit 76fd0f2d4f53 · 2022-05-22T14:41:21.000+02:00
diff --git a/src/Framework/Framework/Compilation/Binding/GeneralBindingPropertyResolvers.cs b/src/Framework/Framework/Compilation/Binding/GeneralBindingPropertyResolvers.cs
@@ -414,12 +414,13 @@ public ThisBindingProperty GetThisBinding(IBinding binding, DataContextStack sta
             return new ThisBindingProperty(thisBinding);
         }
 
-        public CollectionElementDataContextBindingProperty GetCollectionElementDataContext(DataContextStack dataContext, ResultTypeBindingProperty resultType)
+        public CollectionElementDataContextBindingProperty GetCollectionElementDataContext(DataContextStack dataContext, ResultTypeBindingProperty resultType, IBinding binding)
         {
             return new CollectionElementDataContextBindingProperty(DataContextStack.Create(
                 ReflectionUtils.GetEnumerableType(resultType.Type).NotNull(),
                 parent: dataContext,
-                extensionParameters: new CollectionElementDataContextChangeAttribute(0).GetExtensionParameters(new ResolvedTypeDescriptor(dataContext.DataContextType)).ToArray()
+                extensionParameters: new CollectionElementDataContextChangeAttribute(0).GetExtensionParameters(new ResolvedTypeDescriptor(dataContext.DataContextType)).ToArray(),
+                serverSideOnly: binding is not IValueBinding
             ));
         }
 
diff --git a/src/Framework/Framework/Controls/DataItemContainer.cs b/src/Framework/Framework/Controls/DataItemContainer.cs
@@ -56,16 +56,17 @@ public int? DataItemIndex
             set { this.index = value; SetValue(Internal.UniqueIDProperty, value?.ToString()); }
         }
 
+        public bool RenderItemBinding { get; set; } = true;
 
         protected override void RenderControl(IHtmlWriter writer, IDotvvmRequestContext context)
         {
             var maybeIndex = DataItemIndex;
-            if (maybeIndex is int index)
+            if (RenderItemBinding && maybeIndex is int index)
                 writer.WriteKnockoutDataBindComment("dotvvm-SSR-item", index.ToString());
 
             base.RenderControl(writer, context);
 
-            if (maybeIndex is int)
+            if (RenderItemBinding && maybeIndex is int)
                 writer.WriteKnockoutDataBindEndComment();
         }
     }
diff --git a/src/Framework/Framework/Controls/EmptyData.cs b/src/Framework/Framework/Controls/EmptyData.cs
@@ -49,14 +49,15 @@ public EmptyData()
 
         protected override void RenderControl(IHtmlWriter writer, IDotvvmRequestContext context)
         {
+            var dataSourceBinding = GetValueBinding(DataSourceProperty);
             TagName = WrapperTagName;
-            // if RenderOnServer && DataSource is not empty then don't render anything
-            if (!RenderOnServer || GetIEnumerableFromDataSource()?.GetEnumerator()?.MoveNext() != true)
+            // if DataSource is resource binding && DataSource is not empty then don't render anything
+            if (dataSourceBinding is {} || GetIEnumerableFromDataSource()?.GetEnumerator()?.MoveNext() != true)
             {
-                if (!RenderOnServer)
+                if (dataSourceBinding is {})
                 {
-                    var visibleBinding = GetBinding(DataSourceProperty)
-                        .NotNull("DataSource property must contain a binding")
+                    var visibleBinding =
+                        dataSourceBinding
                         .GetProperty<DataSourceLengthBinding>().Binding
                         .GetProperty<IsMoreThanZeroBindingProperty>().Binding
                         .GetProperty<NegatedBindingExpression>().Binding
diff --git a/src/Framework/Framework/Controls/GridView.cs b/src/Framework/Framework/Controls/GridView.cs
@@ -431,7 +431,7 @@ protected override void RenderContents(IHtmlWriter writer, IDotvvmRequestContext
             head?.Render(writer, context);
 
             // render body
-            var foreachBinding = GetForeachDataBindExpression().GetKnockoutBindingExpression(this);
+            var foreachBinding = TryGetKnockoutForeachingExpression().NotNull("GridView does not support DataSource={resource: ...} at this moment.");
             if (RenderOnServer)
             {
                 writer.AddKnockoutDataBind("dotvvm-SSR-foreach", "{data:" + foreachBinding + "}");
@@ -536,7 +536,8 @@ protected override void AddAttributesToRender(IHtmlWriter writer, IDotvvmRequest
             var mapping = userColumnMappingService.GetMapping(itemType!);
             var mappingJson = JsonConvert.SerializeObject(mapping);
 
-            writer.AddKnockoutDataBind("dotvvm-gridviewdataset", $"{{'mapping':{mappingJson},'dataSet':{GetDataSourceBinding().GetKnockoutBindingExpression(this, unwrapped: true)}}}");
+            var dataBinding = TryGetKnockoutForeachingExpression(unwrapped: true).NotNull("GridView does not support DataSource={resource: ...} at this moment.");
+            writer.AddKnockoutDataBind("dotvvm-gridviewdataset", $"{{'mapping':{mappingJson},'dataSet':{dataBinding}}}");
             base.AddAttributesToRender(writer, context);
         }
 
diff --git a/src/Framework/Framework/Controls/HierarchyRepeater.cs b/src/Framework/Framework/Controls/HierarchyRepeater.cs
@@ -184,7 +184,7 @@ private void SetChildren(IDotvvmRequestContext context, bool renderClientTemplat
                 Children.Add(clientRootLevel);
                 clientRootLevel.AppendChildren(new HierarchyRepeaterLevel {
                     IsRoot = true,
-                    ForeachExpression = GetForeachDataBindExpression().GetKnockoutBindingExpression(this),
+                    ForeachExpression = this.TryGetKnockoutForeachingExpression(),
                     ItemTemplateId = clientItemTemplateId,
                 });
             }
diff --git a/src/Framework/Framework/Controls/ItemsControl.cs b/src/Framework/Framework/Controls/ItemsControl.cs
@@ -14,6 +14,8 @@
 using System.Linq.Expressions;
 using DotVVM.Framework.Hosting;
 using Microsoft.Extensions.DependencyInjection;
+using FastExpressionCompiler;
+using DotVVM.Framework.Compilation;
 
 namespace DotVVM.Framework.Controls
 {
@@ -55,29 +57,46 @@ public ItemsControl(string tagName) : base(tagName, false)
         /// <summary>
         /// Gets the data source binding.
         /// </summary>
-        protected IValueBinding GetDataSourceBinding()
+        protected IStaticValueBinding GetDataSourceBinding()
         {
-            var binding = GetValueBinding(DataSourceProperty);
-            if (binding == null)
+            var binding = GetBinding(DataSourceProperty);
+            if (binding is null)
             {
                 throw new DotvvmControlException(this, $"The DataSource property of the '{GetType().Name}' control must be set!");
             }
-            return binding;
+            if (binding is not IStaticValueBinding resourceBinding)
+                throw new BindingHelper.BindingNotSupportedException(binding) { RelatedControl = this };
+            return resourceBinding;
         }
 
         protected IValueBinding GetItemBinding()
         {
-            return (IValueBinding)GetForeachDataBindExpression().GetProperty<DataSourceCurrentElementBinding>().Binding;
+            return GetForeachDataBindExpression().GetProperty<DataSourceCurrentElementBinding>().Binding as IValueBinding ??
+                throw new DotvvmControlException(this, $"The Item property of the '{GetType().Name}' control must be set to a value binding!");
         }
 
         public IEnumerable? GetIEnumerableFromDataSource() =>
             (IEnumerable?)GetForeachDataBindExpression().Evaluate(this);
 
-        protected IValueBinding GetForeachDataBindExpression() =>
-            (IValueBinding)GetDataSourceBinding().GetProperty<DataSourceAccessBinding>().Binding;
+        protected IStaticValueBinding GetForeachDataBindExpression() =>
+            (IStaticValueBinding)GetDataSourceBinding().GetProperty<DataSourceAccessBinding>().Binding;
 
-        protected string GetPathFragmentExpression() =>
-            GetDataSourceBinding().GetKnockoutBindingExpression(this);
+        protected string? TryGetKnockoutForeachingExpression(bool unwrapped = false) =>
+            (GetForeachDataBindExpression() as IValueBinding)?.GetKnockoutBindingExpression(this, unwrapped);
+
+        protected string GetPathFragmentExpression()
+        {
+            var binding = GetDataSourceBinding();
+            var stringified =
+                binding.GetProperty<OriginalStringBindingProperty>(ErrorHandlingMode.ReturnNull)?.Code.Trim() ??
+                binding.GetProperty<KnockoutExpressionBindingProperty>(ErrorHandlingMode.ReturnNull)?.Code.FormatKnockoutScript(this, binding) ??
+                binding.GetProperty<ParsedExpressionBindingProperty>(ErrorHandlingMode.ReturnNull)?.Expression.ToCSharpString();
+
+            if (stringified is null)
+                throw new DotvvmControlException(this, $"Can't create path fragment from binding {binding}, it does not have OriginalString, ParsedExpression, nor KnockoutExpression property.");
+        
+            return stringified;
+        }
 
         [ApplyControlStyle]
         public static void OnCompilation(ResolvedControl control, BindingCompilationService bindingService)
@@ -87,9 +106,10 @@ public static void OnCompilation(ResolvedControl control, BindingCompilationServ
             if (!(dataSourceProperty is ResolvedPropertyBinding dataSourceBinding)) return;
 
             var dataContext = dataSourceBinding.Binding.Binding.GetProperty<CollectionElementDataContextBindingProperty>().DataContext;
+            var bindingType = dataContext.ServerSideOnly ? BindingParserOptions.Resource : BindingParserOptions.Value;
 
             control.SetProperty(new ResolvedPropertyBinding(Internal.CurrentIndexBindingProperty,
-                new ResolvedBinding(bindingService, new Compilation.BindingParserOptions(typeof(ValueBindingExpression)), dataContext,
+                new ResolvedBinding(bindingService, bindingType, dataContext,
                 parsedExpression: Expression.Parameter(typeof(int), "_index").AddParameterAnnotation(
                     new BindingParameterAnnotation(dataContext, new CurrentCollectionIndexExtensionParameter())))));
         }
diff --git a/src/Framework/Framework/Controls/Repeater.cs b/src/Framework/Framework/Controls/Repeater.cs
@@ -9,6 +9,7 @@
 using System.Diagnostics;
 using System.Linq;
 using System.Runtime.CompilerServices;
+using DotVVM.Framework.Utils;
 
 namespace DotVVM.Framework.Controls
 {
@@ -145,16 +146,19 @@ protected override void RenderBeginTag(IHtmlWriter writer, IDotvvmRequestContext
         {
             TagName = WrapperTagName;
 
-            var (bindingName, bindingValue) = RenderOnServer ?
-                                              ("dotvvm-SSR-foreach", GetServerSideForeachBindingGroup()) :
-                                              GetForeachKnockoutBindingGroup(context);
-            if (RenderWrapperTag)
+            if (GetValueBinding(DataSourceProperty) is {})
             {
-                writer.AddKnockoutDataBind(bindingName, bindingValue);
-            }
-            else
-            {
-                writer.WriteKnockoutDataBindComment(bindingName, bindingValue.ToString());
+                var (bindingName, bindingValue) = RenderOnServer ?
+                                                ("dotvvm-SSR-foreach", GetServerSideForeachBindingGroup()) :
+                                                GetForeachKnockoutBindingGroup(context);
+                if (RenderWrapperTag)
+                {
+                    writer.AddKnockoutDataBind(bindingName, bindingValue);
+                }
+                else
+                {
+                    writer.WriteKnockoutDataBindComment(bindingName, bindingValue.ToString());
+                }
             }
 
             if (RenderWrapperTag)
@@ -165,7 +169,7 @@ protected override void RenderBeginTag(IHtmlWriter writer, IDotvvmRequestContext
 
         private KnockoutBindingGroup GetServerSideForeachBindingGroup() =>
             new KnockoutBindingGroup {
-                { "data", GetForeachDataBindExpression().GetKnockoutBindingExpression(this) }
+                { "data", TryGetKnockoutForeachingExpression().NotNull() }
             };
 
         private (string bindingName, KnockoutBindingGroup bindingValue) GetForeachKnockoutBindingGroup(IDotvvmRequestContext context)
@@ -174,7 +178,7 @@ private KnockoutBindingGroup GetServerSideForeachBindingGroup() =>
             var value = new KnockoutBindingGroup();
 
 
-            var javascriptDataSourceExpression = GetForeachDataBindExpression().GetKnockoutBindingExpression(this);
+            var javascriptDataSourceExpression = TryGetKnockoutForeachingExpression().NotNull();
             value.Add(
                 useTemplate ? "foreach" : "data",
                 javascriptDataSourceExpression);
@@ -204,7 +208,6 @@ private KnockoutBindingGroup GetServerSideForeachBindingGroup() =>
         /// </summary>
         protected override void RenderContents(IHtmlWriter writer, IDotvvmRequestContext context)
         {
-            Debug.Assert((clientSideTemplate == null) == this.RenderOnServer);
             if (clientSideTemplate == null)
             {
                 Debug.Assert(clientSeparator == null);
@@ -223,19 +226,18 @@ protected override void RenderEndTag(IHtmlWriter writer, IDotvvmRequestContext c
             {
                 base.RenderEndTag(writer, context);
             }
-            else
+            else if (GetValueBinding(DataSourceProperty) is {})
             {
                 writer.WriteKnockoutDataBindEndComment();
             }
 
             emptyDataContainer?.Render(writer, context);
         }
 
-        private DotvvmControl GetEmptyItem(IDotvvmRequestContext context)
+        private DotvvmControl GetEmptyItem(IDotvvmRequestContext context, IStaticValueBinding dataSourceBinding)
         {
             if (emptyDataContainer == null)
             {
-                var dataSourceBinding = GetDataSourceBinding();
                 emptyDataContainer = new EmptyData();
                 emptyDataContainer.SetValue(EmptyData.RenderWrapperTagProperty, GetValueRaw(RenderWrapperTagProperty));
                 emptyDataContainer.SetValue(EmptyData.WrapperTagNameProperty, GetValueRaw(WrapperTagNameProperty));
@@ -247,24 +249,25 @@ private DotvvmControl GetEmptyItem(IDotvvmRequestContext context)
         }
 
         private ConditionalWeakTable<object, DataItemContainer> childrenCache = new ConditionalWeakTable<object, DataItemContainer>();
-        private DotvvmControl GetItem(IDotvvmRequestContext context, object? item = null, int? index = null, bool allowMemoizationRetrieve = false, bool allowMemoizationStore = false)
+        private DotvvmControl GetItem(IDotvvmRequestContext context, object? item = null, int? index = null, bool serverOnly = false, bool allowMemoizationRetrieve = false, bool allowMemoizationStore = false)
         {
             if (allowMemoizationRetrieve && item != null && childrenCache.TryGetValue(item, out var container2) && container2.Parent == null)
             {
                 Debug.Assert(item == container2.GetValueRaw(DataContextProperty));
-                SetUpServerItem(context, item, (int)index!, container2);
+                SetUpServerItem(context, item, (int)index!, serverOnly, container2);
                 return container2;
             }
 
             var container = new DataItemContainer();
             container.SetDataContextTypeFromDataSource(GetBinding(DataSourceProperty)!);
             if (item == null && index == null)
             {
+                Debug.Assert(!serverOnly);
                 SetUpClientItem(context, container);
             }
             else
             {
-                SetUpServerItem(context, item!, (int)index!, container);
+                SetUpServerItem(context, item!, (int)index!, serverOnly, container);
             }
 
             ItemTemplate.BuildContent(context, container);
@@ -297,24 +300,28 @@ private void SetChildren(IDotvvmRequestContext context, bool renderClientTemplat
             clientSeparator = null;
             clientSideTemplate = null;
 
-            if (DataSource != null)
+            var dataSource = GetIEnumerableFromDataSource();
+            var dataSourceBinding = GetDataSourceBinding();
+            var serverOnly = dataSourceBinding is not IValueBinding;
+
+            if (dataSource != null)
             {
                 var index = 0;
-                foreach (var item in GetIEnumerableFromDataSource()!)
+                foreach (var item in dataSource)
                 {
                     if (SeparatorTemplate != null && index > 0)
                     {
                         Children.Add(GetSeparator(context));
                     }
-                    Children.Add(GetItem(context, item, index,
+                    Children.Add(GetItem(context, item, index, serverOnly,
                         allowMemoizationRetrieve: context.IsPostBack && !memoizeReferences, // on GET request we are not initializing the Repeater twice
                         allowMemoizationStore: memoizeReferences
                     ));
                     index++;
                 }
             }
 
-            if (renderClientTemplate)
+            if (renderClientTemplate && !serverOnly)
             {
                 if (SeparatorTemplate != null)
                 {
@@ -326,7 +333,7 @@ private void SetChildren(IDotvvmRequestContext context, bool renderClientTemplat
 
             if (EmptyDataTemplate != null)
             {
-                Children.Add(GetEmptyItem(context));
+                Children.Add(GetEmptyItem(context, dataSourceBinding));
             }
         }
 
@@ -337,10 +344,11 @@ private void SetUpClientItem(IDotvvmRequestContext context, DataItemContainer co
             container.SetValue(Internal.ClientIDFragmentProperty, this.GetIndexBinding(context));
         }
 
-        private void SetUpServerItem(IDotvvmRequestContext context, object item, int index, DataItemContainer container)
+        private void SetUpServerItem(IDotvvmRequestContext context, object item, int index, bool serverOnly, DataItemContainer container)
         {
             container.DataItemIndex = index;
             container.DataContext = item;
+            container.RenderItemBinding = !serverOnly;
             container.SetValue(Internal.PathFragmentProperty, GetPathFragmentExpression() + "/[" + index + "]");
             container.ID = index.ToString();
         }
diff --git a/src/Tests/ControlTests/ResourceDataContextTests.cs b/src/Tests/ControlTests/ResourceDataContextTests.cs
@@ -68,6 +68,48 @@ public async Task BasicDataContext()
             Assert.AreEqual((string)r.ViewModel.CommandData, "Server o. Customer");
         }
 
+        [TestMethod]
+        public async Task Repeater()
+        {
+            var r = await cth.RunPage(typeof(TestViewModel), @"
+
+                    <!-- without wrapper tag -->
+                    <dot:Repeater DataSource={resource: Customers.Items} RenderWrapperTag=false>
+                        <EmptyDataTemplate> This would be here if the Customers.Items were empty </EmptyDataTemplate>
+                        <SeparatorTemplate>
+                            -------------------
+                        </SeparatorTemplate>
+                        <span class=name data-id={resource: Id}>{{resource: Name}}</span>
+
+                        <span>{{value: _parent.CommandData}}</span>
+
+                        <dot:Button Click={command: _root.TestMethod(Name)} />
+                    </dot:Repeater>
+
+                    <!-- with wrapper tag -->
+                    <dot:Repeater DataSource={resource: Customers} WrapperTagName=div>
+                        <EmptyDataTemplate> This would be here if the Customers.Items were empty </EmptyDataTemplate>
+                        <SeparatorTemplate>
+                            -------------------
+                        </SeparatorTemplate>
+                        <span class=name data-id={resource: Id}>{{resource: Name}}</span>
+
+                        <span>{{value: _parent.CommandData}}</span>
+
+                        <dot:Button Click={command: _root.TestMethod(Name)} />
+                    </dot:Repeater>
+               "
+            );
+
+            check.CheckString(r.FormattedHtml, fileExtension: "html");
+
+            await r.RunCommand("_root.TestMethod(Name)", x => x is TestViewModel.CustomerData { Id: 1 });
+            Assert.AreEqual((string)r.ViewModel.CommandData, "One");
+
+            await r.RunCommand("_root.TestMethod(Name)", x => x is TestViewModel.CustomerData { Id: 2 });
+            Assert.AreEqual((string)r.ViewModel.CommandData, "Two");
+        }
+
         public class TestViewModel: DotvvmViewModelBase
         {
             public string NullableString { get; } = null;
diff --git a/src/Tests/ControlTests/testoutputs/ResourceDataContextTests.Repeater.html b/src/Tests/ControlTests/testoutputs/ResourceDataContextTests.Repeater.html

Original file line number	Diff line number	Diff line change
`@@ -414,12 +414,13 @@ public ThisBindingProperty GetThisBinding(IBinding binding, DataContextStack sta`
`414`	`414`	`return new ThisBindingProperty(thisBinding);`
`415`	`415`	`}`
`416`	`416`
`417`		`- public CollectionElementDataContextBindingProperty GetCollectionElementDataContext(DataContextStack dataContext, ResultTypeBindingProperty resultType)`
	`417`	`+ public CollectionElementDataContextBindingProperty GetCollectionElementDataContext(DataContextStack dataContext, ResultTypeBindingProperty resultType, IBinding binding)`
`418`	`418`	`{`
`419`	`419`	`return new CollectionElementDataContextBindingProperty(DataContextStack.Create(`
`420`	`420`	`ReflectionUtils.GetEnumerableType(resultType.Type).NotNull(),`
`421`	`421`	`parent: dataContext,`
`422`		`- extensionParameters: new CollectionElementDataContextChangeAttribute(0).GetExtensionParameters(new ResolvedTypeDescriptor(dataContext.DataContextType)).ToArray()`
	`422`	`+ extensionParameters: new CollectionElementDataContextChangeAttribute(0).GetExtensionParameters(new ResolvedTypeDescriptor(dataContext.DataContextType)).ToArray(),`
	`423`	`+ serverSideOnly: binding is not IValueBinding`
`423`	`424`	`));`
`424`	`425`	`}`
`425`	`426`
Original file line number	Diff line number	Diff line change
`@@ -56,16 +56,17 @@ public int? DataItemIndex`
`56`	`56`	`set { this.index = value; SetValue(Internal.UniqueIDProperty, value?.ToString()); }`
`57`	`57`	`}`
`58`	`58`
	`59`	`+ public bool RenderItemBinding { get; set; } = true;`
`59`	`60`
`60`	`61`	`protected override void RenderControl(IHtmlWriter writer, IDotvvmRequestContext context)`
`61`	`62`	`{`
`62`	`63`	`var maybeIndex = DataItemIndex;`
`63`		`- if (maybeIndex is int index)`
	`64`	`+ if (RenderItemBinding && maybeIndex is int index)`
`64`	`65`	`writer.WriteKnockoutDataBindComment("dotvvm-SSR-item", index.ToString());`
`65`	`66`
`66`	`67`	`base.RenderControl(writer, context);`
`67`	`68`
`68`		`- if (maybeIndex is int)`
	`69`	`+ if (RenderItemBinding && maybeIndex is int)`
`69`	`70`	`writer.WriteKnockoutDataBindEndComment();`
`70`	`71`	`}`
`71`	`72`	`}`
Original file line number	Diff line number	Diff line change
`@@ -184,7 +184,7 @@ private void SetChildren(IDotvvmRequestContext context, bool renderClientTemplat`
`184`	`184`	`Children.Add(clientRootLevel);`
`185`	`185`	`clientRootLevel.AppendChildren(new HierarchyRepeaterLevel {`
`186`	`186`	`IsRoot = true,`
`187`		`- ForeachExpression = GetForeachDataBindExpression().GetKnockoutBindingExpression(this),`
	`187`	`+ ForeachExpression = this.TryGetKnockoutForeachingExpression(),`
`188`	`188`	`ItemTemplateId = clientItemTemplateId,`
`189`	`189`	`});`
`190`	`190`	`}`
Original file line number	Diff line number	Diff line change
`@@ -9,6 +9,7 @@`
`9`	`9`	`using System.Diagnostics;`
`10`	`10`	`using System.Linq;`
`11`	`11`	`using System.Runtime.CompilerServices;`
	`12`	`+using DotVVM.Framework.Utils;`
`12`	`13`
`13`	`14`	`namespace DotVVM.Framework.Controls`
`14`	`15`	`{`
`@@ -145,16 +146,19 @@ protected override void RenderBeginTag(IHtmlWriter writer, IDotvvmRequestContext`
`145`	`146`	`{`
`146`	`147`	`TagName = WrapperTagName;`
`147`	`148`
`148`		`- var (bindingName, bindingValue) = RenderOnServer ?`
`149`		`- ("dotvvm-SSR-foreach", GetServerSideForeachBindingGroup()) :`
`150`		`- GetForeachKnockoutBindingGroup(context);`
`151`		`- if (RenderWrapperTag)`
	`149`	`+ if (GetValueBinding(DataSourceProperty) is {})`
`152`	`150`	`{`
`153`		`- writer.AddKnockoutDataBind(bindingName, bindingValue);`
`154`		`- }`
`155`		`- else`
`156`		`- {`
`157`		`- writer.WriteKnockoutDataBindComment(bindingName, bindingValue.ToString());`
	`151`	`+ var (bindingName, bindingValue) = RenderOnServer ?`
	`152`	`+ ("dotvvm-SSR-foreach", GetServerSideForeachBindingGroup()) :`
	`153`	`+ GetForeachKnockoutBindingGroup(context);`
	`154`	`+ if (RenderWrapperTag)`
	`155`	`+ {`
	`156`	`+ writer.AddKnockoutDataBind(bindingName, bindingValue);`
	`157`	`+ }`
	`158`	`+ else`
	`159`	`+ {`
	`160`	`+ writer.WriteKnockoutDataBindComment(bindingName, bindingValue.ToString());`
	`161`	`+ }`
`158`	`162`	`}`
`159`	`163`
`160`	`164`	`if (RenderWrapperTag)`
`@@ -165,7 +169,7 @@ protected override void RenderBeginTag(IHtmlWriter writer, IDotvvmRequestContext`
`165`	`169`
`166`	`170`	`private KnockoutBindingGroup GetServerSideForeachBindingGroup() =>`
`167`	`171`	`new KnockoutBindingGroup {`
`168`		`- { "data", GetForeachDataBindExpression().GetKnockoutBindingExpression(this) }`
	`172`	`+ { "data", TryGetKnockoutForeachingExpression().NotNull() }`
`169`	`173`	`};`
`170`	`174`
`171`	`175`	`private (string bindingName, KnockoutBindingGroup bindingValue) GetForeachKnockoutBindingGroup(IDotvvmRequestContext context)`
`@@ -174,7 +178,7 @@ private KnockoutBindingGroup GetServerSideForeachBindingGroup() =>`
`174`	`178`	`var value = new KnockoutBindingGroup();`
`175`	`179`
`176`	`180`
`177`		`- var javascriptDataSourceExpression = GetForeachDataBindExpression().GetKnockoutBindingExpression(this);`
	`181`	`+ var javascriptDataSourceExpression = TryGetKnockoutForeachingExpression().NotNull();`
`178`	`182`	`value.Add(`
`179`	`183`	`useTemplate ? "foreach" : "data",`
`180`	`184`	`javascriptDataSourceExpression);`
`@@ -204,7 +208,6 @@ private KnockoutBindingGroup GetServerSideForeachBindingGroup() =>`
`204`	`208`	`/// </summary>`
`205`	`209`	`protected override void RenderContents(IHtmlWriter writer, IDotvvmRequestContext context)`
`206`	`210`	`{`
`207`		`- Debug.Assert((clientSideTemplate == null) == this.RenderOnServer);`
`208`	`211`	`if (clientSideTemplate == null)`
`209`	`212`	`{`
`210`	`213`	`Debug.Assert(clientSeparator == null);`
`@@ -223,19 +226,18 @@ protected override void RenderEndTag(IHtmlWriter writer, IDotvvmRequestContext c`
`223`	`226`	`{`
`224`	`227`	`base.RenderEndTag(writer, context);`
`225`	`228`	`}`
`226`		`- else`
	`229`	`+ else if (GetValueBinding(DataSourceProperty) is {})`
`227`	`230`	`{`
`228`	`231`	`writer.WriteKnockoutDataBindEndComment();`
`229`	`232`	`}`
`230`	`233`
`231`	`234`	`emptyDataContainer?.Render(writer, context);`
`232`	`235`	`}`
`233`	`236`
`234`		`- private DotvvmControl GetEmptyItem(IDotvvmRequestContext context)`
	`237`	`+ private DotvvmControl GetEmptyItem(IDotvvmRequestContext context, IStaticValueBinding dataSourceBinding)`
`235`	`238`	`{`
`236`	`239`	`if (emptyDataContainer == null)`
`237`	`240`	`{`
`238`		`- var dataSourceBinding = GetDataSourceBinding();`
`239`	`241`	`emptyDataContainer = new EmptyData();`
`240`	`242`	`emptyDataContainer.SetValue(EmptyData.RenderWrapperTagProperty, GetValueRaw(RenderWrapperTagProperty));`
`241`	`243`	`emptyDataContainer.SetValue(EmptyData.WrapperTagNameProperty, GetValueRaw(WrapperTagNameProperty));`
`@@ -247,24 +249,25 @@ private DotvvmControl GetEmptyItem(IDotvvmRequestContext context)`
`247`	`249`	`}`
`248`	`250`
`249`	`251`	`private ConditionalWeakTable<object, DataItemContainer> childrenCache = new ConditionalWeakTable<object, DataItemContainer>();`
`250`		`- private DotvvmControl GetItem(IDotvvmRequestContext context, object? item = null, int? index = null, bool allowMemoizationRetrieve = false, bool allowMemoizationStore = false)`
	`252`	`+ private DotvvmControl GetItem(IDotvvmRequestContext context, object? item = null, int? index = null, bool serverOnly = false, bool allowMemoizationRetrieve = false, bool allowMemoizationStore = false)`
`251`	`253`	`{`
`252`	`254`	`if (allowMemoizationRetrieve && item != null && childrenCache.TryGetValue(item, out var container2) && container2.Parent == null)`
`253`	`255`	`{`
`254`	`256`	`Debug.Assert(item == container2.GetValueRaw(DataContextProperty));`
`255`		`- SetUpServerItem(context, item, (int)index!, container2);`
	`257`	`+ SetUpServerItem(context, item, (int)index!, serverOnly, container2);`
`256`	`258`	`return container2;`
`257`	`259`	`}`
`258`	`260`
`259`	`261`	`var container = new DataItemContainer();`
`260`	`262`	`container.SetDataContextTypeFromDataSource(GetBinding(DataSourceProperty)!);`
`261`	`263`	`if (item == null && index == null)`
`262`	`264`	`{`
	`265`	`+ Debug.Assert(!serverOnly);`
`263`	`266`	`SetUpClientItem(context, container);`
`264`	`267`	`}`
`265`	`268`	`else`
`266`	`269`	`{`
`267`		`- SetUpServerItem(context, item!, (int)index!, container);`
	`270`	`+ SetUpServerItem(context, item!, (int)index!, serverOnly, container);`
`268`	`271`	`}`
`269`	`272`
`270`	`273`	`ItemTemplate.BuildContent(context, container);`
`@@ -297,24 +300,28 @@ private void SetChildren(IDotvvmRequestContext context, bool renderClientTemplat`
`297`	`300`	`clientSeparator = null;`
`298`	`301`	`clientSideTemplate = null;`
`299`	`302`
`300`		`- if (DataSource != null)`
	`303`	`+ var dataSource = GetIEnumerableFromDataSource();`
	`304`	`+ var dataSourceBinding = GetDataSourceBinding();`
	`305`	`+ var serverOnly = dataSourceBinding is not IValueBinding;`
	`306`	`+`
	`307`	`+ if (dataSource != null)`
`301`	`308`	`{`
`302`	`309`	`var index = 0;`
`303`		`- foreach (var item in GetIEnumerableFromDataSource()!)`
	`310`	`+ foreach (var item in dataSource)`
`304`	`311`	`{`
`305`	`312`	`if (SeparatorTemplate != null && index > 0)`
`306`	`313`	`{`
`307`	`314`	`Children.Add(GetSeparator(context));`
`308`	`315`	`}`
`309`		`- Children.Add(GetItem(context, item, index,`
	`316`	`+ Children.Add(GetItem(context, item, index, serverOnly,`
`310`	`317`	`allowMemoizationRetrieve: context.IsPostBack && !memoizeReferences, // on GET request we are not initializing the Repeater twice`
`311`	`318`	`allowMemoizationStore: memoizeReferences`
`312`	`319`	`));`
`313`	`320`	`index++;`
`314`	`321`	`}`
`315`	`322`	`}`
`316`	`323`
`317`		`- if (renderClientTemplate)`
	`324`	`+ if (renderClientTemplate && !serverOnly)`
`318`	`325`	`{`
`319`	`326`	`if (SeparatorTemplate != null)`
`320`	`327`	`{`
`@@ -326,7 +333,7 @@ private void SetChildren(IDotvvmRequestContext context, bool renderClientTemplat`
`326`	`333`
`327`	`334`	`if (EmptyDataTemplate != null)`
`328`	`335`	`{`
`329`		`- Children.Add(GetEmptyItem(context));`
	`336`	`+ Children.Add(GetEmptyItem(context, dataSourceBinding));`
`330`	`337`	`}`
`331`	`338`	`}`
`332`	`339`
`@@ -337,10 +344,11 @@ private void SetUpClientItem(IDotvvmRequestContext context, DataItemContainer co`
`337`	`344`	`container.SetValue(Internal.ClientIDFragmentProperty, this.GetIndexBinding(context));`
`338`	`345`	`}`
`339`	`346`
`340`		`- private void SetUpServerItem(IDotvvmRequestContext context, object item, int index, DataItemContainer container)`
	`347`	`+ private void SetUpServerItem(IDotvvmRequestContext context, object item, int index, bool serverOnly, DataItemContainer container)`
`341`	`348`	`{`
`342`	`349`	`container.DataItemIndex = index;`
`343`	`350`	`container.DataContext = item;`
	`351`	`+ container.RenderItemBinding = !serverOnly;`
`344`	`352`	`container.SetValue(Internal.PathFragmentProperty, GetPathFragmentExpression() + "/[" + index + "]");`
`345`	`353`	`container.ID = index.ToString();`
`346`	`354`	`}`