在不了解projects内容的情况下，很难识别问题。请参考下面的示例，它可能会帮助您解决问题。

// Sample projects array
const projects = [
  { coursename: 'Web Development', fee: 200 },
  { coursename: 'Data Science', fee: 250 },
  { coursename: 'Mobile App Development', fee: 180 },
  { coursename: 'Graphic Design', fee: 150 },
];
// Function to check for duplicate entry
function isDuplicateEntry(coursename, fee) {
    for (var i = 0; i < projects.length; i++) {
        if (projects[i].coursename === coursename && projects[i].fee === fee) {
            return true; // Duplicate entry found
        }
    }
    return false; // No duplicate entry found
}
// Example usage
const duplicateCheck1 = isDuplicateEntry('Data Science', 250);
const duplicateCheck2 = isDuplicateEntry('Web Development', 150);
console.log('Duplicate check for "Data Science" with fee 250:', duplicateCheck1);
console.log('Duplicate check for "Web Development" with fee 150:', duplicateCheck2);

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你好像是从后台加载数据，然后检查你的当前实体是否与js代码重复？（我看不到你所有的代码，如果不是，请指出）
我们通常会检查一个实体是否在服务器上重复，以避免加载不必要的数据，当多个用户同时添加实体时，性能会更好。
在asp.net核心MVC项目中，您可以按照此文档尝试远程验证
举个简单的例子：
产品型号：

public class MyEntity
{
    public int Id { get; set; }
    [Remote(action: "Validate", controller: "MyEntities", AdditionalFields = nameof(Fee))]
    public string Name { get; set; }
    [Remote(action: "Validate", controller: "MyEntities", AdditionalFields = nameof(Name))]
    public string Fee { get; set; }
}

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控制器：

public IActionResult Create()
{
    return View();
}
[HttpPost]
public async Task<IActionResult> Create([Bind("Id,Name,Fee")] MyEntity myEntity)
{
    if (ModelState.IsValid)
    {
        _context.Add(myEntity);
        await _context.SaveChangesAsync();
        return RedirectToAction(nameof(Index));
    }
    return View(myEntity);
}
 [AcceptVerbs("Post","Get")]
 public IActionResult Validate(MyEntity myEntity)
 {
     var duplicated = _context.MyEntity.FirstOrDefault(x=>x.Name==myEntity.Name&&x.Fee==myEntity.Fee)!=null?true:false;
     if (duplicated)
     {
         return Json("An Entity with the same Name& Fee has  already exists");
     }
     return Json(true);
 }

型
检视：

<h1>Create</h1>
<h4>MyEntity</h4>
<hr />
<div class="row">
    <div class="col-md-4">
        <form asp-action="Create">
            <div asp-validation-summary="ModelOnly" class="text-danger"></div>
            <div class="form-group">
                <label asp-for="Name" class="control-label"></label>
                <input asp-for="Name" class="form-control" />
                <span asp-validation-for="Name" class="text-danger"></span>
            </div>
            <div class="form-group">
                <label asp-for="Fee" class="control-label"></label>
                <input asp-for="Fee" class="form-control" />
                <span asp-validation-for="Fee" class="text-danger"></span>
            </div>
            <div class="form-group">
                <input type="submit" value="Create" class="btn btn-primary" />
            </div>
        </form>
    </div>
</div>
<div>
    <a asp-action="Index">Back to List</a>
</div>
<script src="~/lib/jquery/dist/jquery.min.js"></script>
<script src="~/lib/jquery-validation/dist/jquery.validate.min.js"></script>
<script src="~/lib/jquery-validation-unobtrusive/jquery.validate.unobtrusive.min.js"></script>

型
测试结果：

的数据

1.可能是缓存问题。请清除服务器中的缓存并重试2.=区分大小写，验证现有数据和新添加的数据是否相同3.尝试在开发人员选项控制台中进行调试4.或者尝试在#行中使用coursename变量和fee变量的alert语句2和3. 5.可能是小数位的费用可能会导致问题。尝试使用警报或尝试console.log