EF Core 类似条件下的动态列名称

Question

我已经在 asp.net 8 core 中为 jquery 数据表后端创建了通用方法，这是有效的，但我想将其转换为 EF quirybuilder 样式而不是自定义 sql 查询

我尝试了很多，但面临着在where条件下获取动态字段名称的问题

当前工作代码是

public async Task<IActionResult>getdata()
{
    var queryString = Request.QueryString.ToString();
    IDictionary<string, StringValues> qs = QueryHelpers.ParseQuery(queryString);
    var entityType = _context.Model.FindEntityType(typeof(Gate));
    //var entityType = typeof(DTGate);
    var cols = entityType.GetProperties().Select(p => p.Name).ToArray();


    string qry = "select * from " + entityType.GetTableName() + " where 1=1 ";

    string mainConds = " and created_by="+User.Identity.UserId();

    //ordering
    string orderBy = "";
    if (qs.ContainsKey("iSortingCols") && !string.IsNullOrEmpty(qs["iSortingCols"]))
    {
        var numOfSortCols = Convert.ToInt32(qs["iSortingCols"]);
        List<string> dtOrders = new List<string>();
        for (int i = 0; i < numOfSortCols; i++)
        {
            dtOrders.Add(qs["mDataProp_" + Convert.ToInt32(qs["iSortCol_" + i])] + " " + qs["sSortDir_" + i]);
        }
        if (dtOrders.Count > 0)
        {
            orderBy = " ORDER BY " + string.Join(",", dtOrders);
        }
    }

    //main filter
    List<string> filterCondsList = new List<string>();
    if (qs.ContainsKey("sSearch") && !string.IsNullOrEmpty(qs["sSearch"]))
    {
        var searchTerm = qs["sSearch"];
        foreach (var col in cols)
        {
            string thisCond = " " + col + " LIKE '%" + searchTerm + "%'";
            filterCondsList.Add(thisCond);
        }
    }
    string filterConds = "";
    if (filterCondsList.Count > 0)
    {
        filterConds = "(" + string.Join(" OR ", filterCondsList) + ")";
    }


    //column level filtering
    string colConds = "";
    int qsColumns = Convert.ToInt32(qs["iColumns"]);
    for (int i = 0; i < qsColumns; i++)
    {
        var searchableKey = "bSearchable_" + i;
        var cSearchTermIndx = "sSearch_" + i;

        if (qs.ContainsKey(searchableKey) && qs[searchableKey] == "true" && qs.ContainsKey(cSearchTermIndx) && !string.IsNullOrEmpty(qs[cSearchTermIndx]))
        {
            colConds += " AND " + qs["mDataProp_" + i] + " LIKE '%" + qs[cSearchTermIndx] + "%'";
        }
    }
    if (colConds != "")
    {
        colConds = colConds.Substring(4);
    }


    //prepare execute sql query
    string sqlQry = qry + mainConds;
    //int totalRecords = await getTototalRecordsAsync(sqlQry);
    int totalRecords = await _recordCountService.GetTotalRecordsAsync(sqlQry);

    if (!string.IsNullOrEmpty(filterConds))
    {
        sqlQry += " AND " + filterConds;
    }

    if (!string.IsNullOrEmpty(colConds))
    {
        sqlQry += " AND " + colConds;
    }
    int recordsFiltered = await _recordCountService.GetTotalRecordsAsync(sqlQry);
    if (!string.IsNullOrEmpty(orderBy))
    {
        sqlQry += orderBy;
    }

    int displaySkip = Convert.ToInt32(qs["iDisplayStart"]);
    int displayLength = Convert.ToInt32(qs["iDisplayLength"]);

    sqlQry += " OFFSET " + displaySkip + " ROWS FETCH NEXT " + displayLength + " ROWS ONLY";

    var gates = _context.Database.SqlQueryRaw<DTGate>(sqlQry).ToList();

    DataTableResponse<DTGate> response = new DataTableResponse<DTGate>();
    response.draw = qs["sEcho"];
    response.recordsTotal = totalRecords;
    response.recordsFiltered = recordsFiltered;
    response.data = gates;

    var json = JsonConvert.SerializeObject(response);

    return Content(json, "application/json");
}

在上面的代码中没有硬编码输入字段名称，所有字段条件都是动态生成的。

Answer 1

你有两个选择。

1. 只需调用 EF core ExecuteSqlRaw 并将其序列化为您认为可以的任何内容。

2. 创建一个包含 800 个属性或您认为可能发生的其他属性的类。你必须添加所有内容。然后你就可以以正确的方式使用 EF-core，只是永远不要从模型创建数据库，或者使用它来获取对象而不指定你想要的列。