refactor: 更新 MaxFileCount 逻辑

Author: ArgoZhang

src/BootstrapBlazor/Components/Upload/UploadBase.cs

@@ -143,8 +143,20 @@ protected override void OnParametersSet()
     /// <returns></returns>
     protected async Task OnFileChange(InputFileChangeEventArgs args)
     {
-        var fileCount = MaxFileCount ?? 0;
-        fileCount = Math.Max(fileCount, args.FileCount);
+        var fileCount = args.FileCount;
+        if (MaxFileCount.HasValue)
+        {
+            fileCount = MaxFileCount.Value;
+        }
+
+        // 计算剩余可上传数量
+        fileCount = fileCount - Files.Count;
+        if (fileCount <= 0)
+        {
+            // 如果剩余可上传数量小于等于 0 则不允许继续上传
+            return;
+        }
+
         var items = args.GetMultipleFiles(args.FileCount).Take(fileCount).Select(f =>
         {
             var file = new UploadFile()

test/UnitTest/Components/UploadInputTest.cs

@@ -190,6 +190,23 @@ await cut.InvokeAsync(() => input.Instance.OnChange.InvokeAsync(new InputFileCha
         // 重置后不应该包含新上传的文件
         await cut.InvokeAsync(() => cut.Instance.Reset());
         Assert.DoesNotContain("test3.png;test4.png", cut.Markup);
+
+        cut.SetParametersAndRender(pb =>
+        {
+            pb.Add(a => a.DefaultFileList,
+            [
+                new UploadFile() { FileName = "test5.png" },
+                new UploadFile() { FileName = "test6.png" }
+            ]);
+            pb.Add(a => a.Value,
+            [
+                new MockBrowserFile("test5.png"),
+                new MockBrowserFile("test6.png")
+            ]);
+        });
+        Assert.Contains("test5.png;test6.png", cut.Markup);
+        await cut.InvokeAsync(() => cut.Instance.Reset());
+        Assert.DoesNotContain("test5.png;test6.png", cut.Markup);
     }
 
     [Fact]
@@ -233,7 +250,7 @@ public async Task MaxFileCount_Ok()
         var cut = Context.RenderComponent<InputUpload<string>>(pb =>
         {
             pb.Add(a => a.IsMultiple, true);
-            pb.Add(a => a.MaxFileCount, 4);
+            pb.Add(a => a.MaxFileCount, 2);
         });
 
         var input = cut.FindComponent<InputFile>();