c# - 类x.Savechanges(): No suitable method found to override

Question

我想 checkout db.SaveChanges()进行错误处理，并将其放入EFentities类的SaveChanges()方法中，但是我对SaveChanges()遇到此错误:

No suitable method found to override

这是我的代码:

public partial class EFentities
{
    EF db = new EF();

    public override int  SaveChanges()
    {
        try
        {
            return base.SaveChanges();
        }
        catch (DbEntityValidationException ex)
        {
            // Retrieve the error messages as a list of strings.
            var errorMessages = ex.EntityValidationErrors
                    .SelectMany(x => x.ValidationErrors)
                    .Select(x => x.ErrorMessage);

            // Join the list to a single string.
            var fullErrorMessage = string.Join("; ", errorMessages);

            // Combine the original exception message with the new one.
            var exceptionMessage = string.Concat(ex.Message, " The validation errors are: ", fullErrorMessage);

            // Throw a new DbEntityValidationException with the improved exception message.
            throw new DbEntityValidationException(exceptionMessage, ex.EntityValidationErrors);
        }
    }
}

Answer 1

您没有找到合适的方法来覆盖错误，因为您既没有在部分类的另一侧定义SaveChanges()虚拟方法，也没有定义该虚拟方法继承的任何基类。

带有SaveChanges()签名的 System.Data.Entity.DbContext 类中可用的virtual方法如下:

public virtual int SaveChanges()

因此，您应该添加DbContext作为EFEntities继承的基类，以使override关键字起作用:

using System.Data.Entity;

public partial class EFEntities : DbContext // add this base class
{
    public override int SaveChanges()
    {
        // manual override goes here

        return base.SaveChanges();
    }
}