Question

将Fluent API用作OR / M，并为SO post中提到的跟踪列实现UNIQUE。

对于服务器端验证，下面的代码运行正常：

[HttpPost]
public ActionResult Save(Company company)
{
    try
    {
        if (company.Id == 0)
            _context.Companies.Add(company);
        else
        {
            var companyInDb = _context.Companies.Single(c => c.Id == company.Id);
            companyInDb.Name = company.Name;
        }
        _context.SaveChanges();
        return RedirectToAction("Index", "Companies");
    }
    catch (System.Data.Entity.Validation.DbEntityValidationException ex)
    {
        var error = ex.EntityValidationErrors.First().ValidationErrors.First();
        this.ModelState.AddModelError(error.PropertyName, error.ErrorMessage);
        return View("CompanyForm");
    }
}

如何验证服务器端的唯一值？

尝试下面的代码catch根本没有回复

catch (System.Data.SqlClient.SqlException ex)
{
    this.ModelState.AddModelError("Duplicate Value", ex.Message);
    return View("CompanyForm");
}

Answer 1

你可以试试这个：

using System.Data.Entity.Infrastructure;
//....

catch (DbUpdateException e) when ((e?.InnerException?.InnerException as System.Data.SqlClient.SqlException)?.Number == 2601)
{    
    this.ModelState.AddModelError("NameOfColumn", "Item with such NameOfColumn already exist");
}
catch (System.Data.Entity.Validation.DbEntityValidationException ex)
{
    var error = ex.EntityValidationErrors.First().ValidationErrors.First();
    this.ModelState.AddModelError(error.PropertyName, error.ErrorMessage);
}
return View("CompanyForm");

使用Fluent API对唯一约束进行服务器端验证

1 个答案: