feat(OpcDa): add Browse feature (dotnetcore#6565)

* wip: 增加浏览功能

* doc: 增加浏览功能示例

Author: ArgoZhang

src/BootstrapBlazor.Server/BootstrapBlazor.Server.csproj

@@ -60,7 +60,7 @@
     <PackageReference Include="BootstrapBlazor.OctIcon" Version="9.0.4" />
     <PackageReference Include="BootstrapBlazor.OfficeViewer" Version="9.0.0" />
     <PackageReference Include="BootstrapBlazor.OnScreenKeyboard" Version="9.0.1" />
-    <PackageReference Include="BootstrapBlazor.OpcDa" Version="9.0.0" />
+    <PackageReference Include="BootstrapBlazor.OpcDa" Version="9.0.1" />
     <PackageReference Include="BootstrapBlazor.PdfReader" Version="9.0.1" />
     <PackageReference Include="BootstrapBlazor.PdfViewer" Version="9.0.6" />
     <PackageReference Include="BootstrapBlazor.Player" Version="9.0.1" />

src/BootstrapBlazor.Server/Components/Samples/OpcDa.razor

@@ -7,7 +7,7 @@
 
 <PackageTips Name="BootstrapBlazor.OpcDa"/>
 
-<DemoBlock Title="@Localizer["OpcDaNormalTitle"]" Introduction="@Localizer["OpcDaNormalIntro"]" Name="Normal">
+<DemoBlock Title="@Localizer["OpcDaNormalTitle"]" Introduction="@Localizer["OpcDaNormalIntro"]" ShowCode="false" Name="Normal">
     <p class="code-label">1. 点击 <b>连接</b> 按钮与 <code>OpcDa</code> 服务器建立通讯连接</p>
     <p>
         <BootstrapInputGroup>
@@ -42,7 +42,7 @@
 
     <p class="code-label">3. 订阅功能</p>
     <p>通过订阅可以监控一组 <b>位号</b> 数据改变情况，当数据改变时通过 <code>DataChanged</code> 回调方法通知订阅者</p>
-    <div class="row g-3">
+    <p class="row g-3">
         <div class="col-12 col-sm-6">
             <BootstrapInputGroup>
                 <BootstrapInputGroupLabel DisplayText="订阅名称"></BootstrapInputGroupLabel>
@@ -73,5 +73,15 @@
             <Button OnClick="OnCreateSubscription" Text="订阅" IsDisabled="@(!OpcDaServer.IsConnected || _subscribed)"></Button>
             <Button OnClick="OnCancelSubscription" Text="取消" IsDisabled="!_subscribed"></Button>
         </div>
-    </div>
+    </p>
+
+    <p class="code-label">4. 浏览</p>
+    <p>通过调用 <code>OpcDaServer</code> 的 <code>Browse</code> 方法可以构建一个节点树状结构</p>
+    <p>
+        <Button OnClick="OnBrowse" Text="浏览" IsDisabled="!OpcDaServer.IsConnected"></Button>
+    </p>
+    <p>
+        <TreeView Items="_roots" AutoCheckChildren="true" AutoCheckParent="true" ShowIcon="true"
+                  OnExpandNodeAsync="OnExpandNodeAsync"></TreeView>
+    </p>
 </DemoBlock>

src/BootstrapBlazor.Server/Components/Samples/OpcDa.razor.cs

@@ -82,5 +82,33 @@ private void UpdateValues(List<OpcReadItem> items)
 
         InvokeAsync(StateHasChanged);
     }
-}
 
+    private List<TreeViewItem<OpcBrowseElement>> _roots = [];
+
+    private void OnBrowse()
+    {
+        var elements = OpcDaServer.Browse("", new OpcBrowseFilters(), out _);
+        _roots = elements.Select(element => new TreeViewItem<OpcBrowseElement>(element)
+        {
+            Text = element.Name,
+            HasChildren = element.HasChildren,
+            Icon = "fa-solid fa-fw fa-cubes"
+        }).ToList();
+    }
+
+    private Task<IEnumerable<TreeViewItem<OpcBrowseElement>>> OnExpandNodeAsync(TreeViewItem<OpcBrowseElement> element)
+    {
+        var children = OpcDaServer.Browse(element.Value.ItemName, new OpcBrowseFilters(), out _);
+        var items = children.Select(i => new TreeViewItem<OpcBrowseElement>(i)
+        {
+            Text = i.Name,
+            HasChildren = i.HasChildren,
+            Icon = i.HasChildren ? "fa-solid fa-fw fa-cube" : "fa-solid fa-fw fa-wrench"
+        });
+        if (!items.Any())
+        {
+            element.HasChildren = false;
+        }
+        return Task.FromResult(items);
+    }
+}