Queryable.Union 方法实现json格式的字符串合并的具体实例

1.在数据库中以json字符串格式保存，如：[{"name":"张三","time":"8.592","area":"27.27033","conc":"4.12136"},{"name":"李四","time":"9.100","area":"56.21229","conc":"4.57692"}]

2.添加新内容后合并不相同的数据。如果name相同，以最新的数据替换原来的数据。

如：数据库中原保存的数据是[{"name":"张三","time":"8.592","area":"27.27033","conc":"4.12136"},{"name":"李四","time":"9.100","area":"56.21229","conc":"4.57692"}]

新加的数据为[{"name":"张三","time":"12","area":"27.70533","conc":"4.12136"},{"name":"王五","time":"4","area":"77","conc":"8.788"}]

 则替换后的数据为[{"name":"张三","time":"12","area":"27.70533","conc":"4.12136"},{"name":"王五","time":"4","area":"77","conc":"8.788"},{"name":"李四","time":"9.100","area":"56.21229","conc":"4.57692"}]

代码如下：

                    var listown = ser.Deserialize<List<Dictionary<string, string>>>(own.fldImportData);  //原数据
                    var listmodel = ser.Deserialize<List<Dictionary<string, string>>>(model.fldImportData); //新数据
                    IEqualityComparer<Dictionary<string, string>> ec = new EntityComparer();   //自定义的比较类
                    own.fldImportData = ser.Serialize(listmodel.Union(listown, ec));  //合并数据

                    listLeUpdate.Add(own);
                }
                else
                {
                    listLeInsert.Add(model);
                }
            }
            CurrentRepository.UpdateAll(listLeUpdate);
            CurrentRepository.InsertAll(listLeInsert);
            CurrentRepository.Save();
        }
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tblLims_Ana_LE_Import_Common 为数据库中存数据的表

Union() 方法中用到的自定义比较类:

            if (ReferenceEquals(x, null) || ReferenceEquals(y, null))
                return false;

            return x["name"] == y["name"];  //如果名称相同就不追加
        }

        public int GetHashCode(Dictionary<string, string> obj)
        {
            if (ReferenceEquals(obj, null)) return 0;
            int hashName = obj["name"] == null ? 0 : obj["name"].GetHashCode();
            int hashCode = obj["name"] == null ? 0 : obj["name"].GetHashCode();
            return hashName ^ hashCode;
        }
    }
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