使用标识主键将新实体插入上下文

Question

我想在我的SQL表中插入一条新记录.我试过了:

        public void CreateComment(int questionId, string comment)
        {
            QuestionComment questionComment = context.TableName.Create();//1*
            questionComment.propertyThatIsNotAConstraint= questionId;
            questionComment.body = comment;
            context.QuestionComments.Add(questionComment);
            context.SaveChanges();//ERROR...
        }

1*我很惊讶地看到intellisense告诉我: "请注意,新实体未添加或附加到集合中"

错误读取:

"违反PRIMARY KEY约束'PK_TableName'.无法在对象'dbo.TableName'中插入重复键.重复键值为(0).\ r \n语句已终止."

问题是它questionComment有PK:questionComment.Id默认为0.它需要是下一个可用的标识,否则不会填充并执行"正常"标识插入.

实体框架如何期望我处理这个场景？

按照要求:

//------------------------------------------------------------------------------
// <auto-generated>
//    This code was generated from a template.
//
//    Manual changes to this file may cause unexpected behavior in your application.
//    Manual changes to this file will be overwritten if the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------

    namespace Feedback.Models
    {
        using System;
        using System.Collections.Generic;

        public partial class QuestionComment
        {
            public int id { get; set; }
            public int questionId { get; set; }
            public string body { get; set; }
            public int commentIndex { get; set; }
        }
    }

Answer 1

我通过以下方式修复:

1. 转到SQL并确保表中的"Identity Specification"> Is Identity>设置为Yes.如果必须更改数据库,则更新*.edmx文件.

2. 检查*.edmx>实体属性> StoreGeneratedPattern以获取标识,以确保将其设置为Identity