Improve SSE supports.

Common/Data/PagingJsonLoader.cs

@@ -201,6 +201,11 @@ public BaseJsonPagingLoader(bool disableAutoRaise)
     /// </summary>
     public int PageIndex { get; private set; } = -1;
 
+    /// <summary>
+    /// Gets or sets the additional data.
+    /// </summary>
+    public object Tag { get; set; }
+
     /// <summary>
     /// Gets data.
     /// </summary>

Common/UI/Converters.cs

@@ -165,6 +165,80 @@ protected virtual object CreateValue(object parameter, string language)
         => DependencyProperty.UnsetValue;
 }
 
+/// <summary>
+/// The visibility converter about the value is not null or empty.
+/// </summary>
+public class EmptyToCollapseConverter : IValueConverter
+{
+    /// <summary>
+    /// Converts a source to target.
+    /// </summary>
+    /// <param name="value">The input value to convert.</param>
+    /// <param name="targetType">The type of target.</param>
+    /// <param name="parameter">The converter parameter.</param>
+    /// <param name="language">The language code.</param>
+    /// <returns>The result converted.</returns>
+    public object Convert(object value, Type targetType, object parameter, string language)
+        => VisualUtility.ConvertFromBoolean(value is string s ? !string.IsNullOrEmpty(s) : value is not null, targetType, true);
+
+    /// <summary>
+    /// Converts the source back.
+    /// </summary>
+    /// <param name="value">The input value to convert back.</param>
+    /// <param name="targetType">The type of target.</param>
+    /// <param name="parameter">The converter parameter.</param>
+    /// <param name="language">The language code.</param>
+    /// <returns>The result converted back.</returns>
+    public object ConvertBack(object value, Type targetType, object parameter, string language)
+        => VisualUtility.ConvertToBoolean(value) != true ? null : CreateValue(parameter, language);
+
+    /// <summary>
+    /// Creates the value.
+    /// </summary>
+    /// <param name="parameter">The converter parameter.</param>
+    /// <param name="language">The language code.</param>
+    /// <returns>The result created to convert back.</returns>
+    protected virtual object CreateValue(object parameter, string language)
+        => DependencyProperty.UnsetValue;
+}
+
+/// <summary>
+/// The visibility converter about the value is null or empty.
+/// </summary>
+public class EmptyToVisibleConverter : IValueConverter
+{
+    /// <summary>
+    /// Converts a source to target.
+    /// </summary>
+    /// <param name="value">The input value to convert.</param>
+    /// <param name="targetType">The type of target.</param>
+    /// <param name="parameter">The converter parameter.</param>
+    /// <param name="language">The language code.</param>
+    /// <returns>The result converted.</returns>
+    public object Convert(object value, Type targetType, object parameter, string language)
+        => VisualUtility.ConvertFromBoolean(value is string s ? string.IsNullOrEmpty(s) : value is null, targetType, true);
+
+    /// <summary>
+    /// Converts the source back.
+    /// </summary>
+    /// <param name="value">The input value to convert back.</param>
+    /// <param name="targetType">The type of target.</param>
+    /// <param name="parameter">The converter parameter.</param>
+    /// <param name="language">The language code.</param>
+    /// <returns>The result converted back.</returns>
+    public object ConvertBack(object value, Type targetType, object parameter, string language)
+        => VisualUtility.ConvertToBoolean(value) != false ? null : CreateValue(parameter, language);
+
+    /// <summary>
+    /// Creates the value.
+    /// </summary>
+    /// <param name="parameter">The converter parameter.</param>
+    /// <param name="language">The language code.</param>
+    /// <returns>The result created to convert back.</returns>
+    protected virtual object CreateValue(object parameter, string language)
+        => DependencyProperty.UnsetValue;
+}
+
 /// <summary>
 /// The two-way converter of visibility and boolean.
 /// </summary>

Console/README.md

@@ -118,5 +118,5 @@ DefaultConsole.WriteLine(new LinearGradientConsoleStyle(
     Color.FromArgb(85, 168, 255))   // To color
     {
         Bold = true     // Additional font style
-    },"Trivial Sample");
+    }, "Trivial Sample");
 ```

Site/Controllers/TestController.cs

@@ -1,6 +1,7 @@
 using Microsoft.AspNetCore.Mvc;
 using System.Text.Json.Nodes;
 using Trivial.Collection;
+using Trivial.Data;
 using Trivial.Net;
 using Trivial.Security;
 using Trivial.Text;
@@ -50,7 +51,18 @@ public ActionResult GetData()
     [HttpGet("Stream")]
     public IActionResult Stream()
     {
-        var sse = DemoServer.Instance.StreamData(10);
+        var sse = DemoServer.Instance.StreamDataAsync(10);
         return sse.ToActionResult();
     }
+
+    [HttpGet("Jsonl")]
+    public IActionResult ListData()
+    {
+        var sse = DemoServer.Instance.ListDataAsync(10);
+        return sse.ToActionResult();
+    }
+
+    [HttpGet("Items")]
+    public IActionResult PushData()
+        => ControllerExtensions.ToActionResult<JsonObjectNode>(DemoServer.Instance.AppendToAsync);
 }

Site/DemoServer.cs

@@ -1,4 +1,6 @@
-using System.Text.Json.Serialization;
+using Microsoft.AspNetCore.CookiePolicy;
+using System.Text.Json.Serialization;
+using Trivial.Data;
 using Trivial.Net;
 using Trivial.Reflection;
 using Trivial.Security;
@@ -52,18 +54,62 @@ protected override async Task<SelectionRelationship<UserModel, TokenInfo>> SignI
         });
     }
 
-    public async IAsyncEnumerable<ServerSentEventInfo> StreamData(int count)
+    public async IAsyncEnumerable<JsonObjectNode> ListDataAsync(int count)
     {
         for (var i = 0; i < count; i++)
         {
             await Task.Delay(1000);
-            yield return new ServerSentEventInfo("test-data", "message", new JsonObjectNode()
+            yield return new JsonObjectNode()
             {
                 { "action", "add" },
                 { "value", Guid.NewGuid() },
                 { "index", i }
+            };
+        }
+    }
+
+    public async IAsyncEnumerable<ServerSentEventInfo> StreamDataAsync(int count)
+    {
+        var col = ListDataAsync(count);
+        await foreach (var item in col)
+        {
+            yield return new ServerSentEventInfo("test-data", "message", item);
+        }
+    }
+
+    public async Task AppendToAsync(CollectionResultBuilder<JsonObjectNode> builder)
+    {
+        if (builder == null) return;
+        var col = ListDataAsync(10);
+        builder.SetTrackingId(Guid.NewGuid().ToString());
+        builder.PatchAdditionalInfo(new()
+        {
+            { "name", "test data" },
+            { "status", "streaming" },
+            { "push", 0 },
+        });
+        builder.SetOffset(0, 10, "The item is streaming one by one.");
+        await foreach (var item in col)
+        {
+            builder.Add(item);
+            builder.PatchAdditionalInfo(new()
+            {
+                { "push", builder.Result.CurrentCount }
             });
         }
+        builder.SetMessage("Stream all items successfully.");
+        builder.PatchAdditionalInfo(new()
+        {
+            { "status", "done" }
+        });
+        builder.End();
+
+        // Following - nothing happened.
+        builder.PatchAdditionalInfo(new()
+        {
+            { "status", "no more" }
+        });
+        builder.End();
     }
 
     public ISignatureProvider GetSignatureProvider<T>(T payload, string id)