🆕 (Button): simplify the usage of icon buttons (#607)

Author: capdiem

src/Component/BlazorComponent/Components/Button/BButton.razor

@@ -17,12 +17,7 @@
             __internal_preventDefault_onclick="@OnClickPreventDefault"
             @attributes="Attributes">
 
-            @if (HasLoader)
-            {
-                @RenderPart(typeof(BButtonLoader<>))
-            }
-
-            @RenderPart(typeof(BButtonContent<>))
+            @GenContent()
         </KeyTransitionElement>
     }
     else
@@ -39,13 +34,56 @@
             __internal_stopPropagation_onclick="@OnClickStopPropagation"
             __internal_preventDefault_onclick="@OnClickPreventDefault"
             @attributes="Attributes">
+            @GenContent()
+        </ShowTransitionElement>
+    }
+</CascadingValue>
+
+@code {
 
-            @if (HasLoader)
+
+    RenderFragment GenContent() => __builder =>
+    {
+        if (HasLoader)
+        {
+            @if (Loading)
             {
-                @RenderPart(typeof(BButtonLoader<>))
+                <div class="@CssProvider.GetClass("loader")" style="@CssProvider.GetStyle("loader")">
+                    @if (LoaderContent == null)
+                    {
+                        <BProgressCircular @attributes="@GetAttributes(typeof(BProgressCircular))"></BProgressCircular>
+                    }
+                    else
+                    {
+                        @LoaderContent
+                    }
+                </div>
             }
+        }
 
-            @RenderPart(typeof(BButtonContent<>))
-        </ShowTransitionElement>
-    }
-</CascadingValue>
+        <span class="@CssProvider.GetClass("content")" style="@CssProvider.GetStyle("content")">
+            @GenIcon("left")
+            @GenIcon()
+            @ChildContent
+            @GenIcon("right")
+        </span>
+    };
+
+    RenderFragment GenIcon(string? position = null) => __builder =>
+    {
+        var (icon, left, right) = position switch
+        {
+            "left" => (LeftIconName, true, false),
+            "right" => (RightIconName, false, true),
+            _ => (IconName, false, false)
+        };
+
+        if (string.IsNullOrWhiteSpace(icon))
+        {
+            return;
+        }
+
+        <BIcon Left="@left" Right="@right" @attributes="@GetAttributes(typeof(BIcon), data: position)">@icon</BIcon>
+    };
+
+}

src/Component/BlazorComponent/Components/Button/BButton.razor.cs

@@ -62,6 +62,15 @@ protected BButton() : base(GroupType.ButtonGroup, "button")
         [Parameter]
         public string? Key { get; set; }
 
+        [Parameter] [MasaApiParameter(ReleasedOn = "v1.5.0")]
+        public string? IconName { get; set; }
+
+        [Parameter] [MasaApiParameter(ReleasedOn = "v1.5.0")]
+        public string? LeftIconName { get; set; }
+        
+        [Parameter] [MasaApiParameter(ReleasedOn = "v1.5.0")]
+        public string? RightIconName { get; set; }
+
         /// <summary>
         /// Determine whether rendering a loader component
         /// </summary>
@@ -71,6 +80,9 @@ protected BButton() : base(GroupType.ButtonGroup, "button")
         /// Set the button's type attribute
         /// </summary>
         protected string TypeAttribute { get; set; } = "button";
+        
+        [MemberNotNullWhen(true, nameof(IconName))]
+        protected bool HasBuiltInIcon => !string.IsNullOrWhiteSpace(IconName);
 
         public bool IsDark
         {