Question

我想为网站建立一个advanced multiple parameters search。
这是我的DBML和ORM模式：
用户可以在此advanced multiple parameters search中搜索具有多个参数（例如大小，楼层，城市，价格等）的房地产。
这是我编写的处理此部分的功能。

 private DataTable linq_search_by_details()
    {
        myDBMLDataContext ctx = new myDBMLDataContext(address);
        var query = ctx.Estates.AsQueryable();
        query = query.Where(c => c.eshId == int.Parse(ddlEshape.SelectedValue.ToString()));
        query = query.Where(c => c.cityId == int.Parse(ddlcity.SelectedValue.ToString()));
        query = query.Where(c => c.ETId == int.Parse(ddlType.SelectedValue.ToString()));
        query = query.Where(c => c.dealingId == int.Parse(ddldeal.SelectedValue.ToString()));
        query = query.Where(c => c.deedId == int.Parse(ddldeed.SelectedValue.ToString()));
        if (!string.IsNullOrEmpty(txtPrepaymentFrom.Value.Trim()))
        {
            query = query.Where(c => int.Parse(c.prepayment) <= int.Parse(txtPrepaymentFrom.Value));
        }
        if (!string.IsNullOrEmpty(txtPrepaymentTo.Value.Trim()))
        {
            query = query.Where(c => int.Parse(c.prepayment) >= int.Parse(txtPrepaymentTo.Value));
        }
        if (!string.IsNullOrEmpty(txtPrepaymentFrom.Value.Trim()) && !string.IsNullOrEmpty(txtPrepaymentTo.Value.Trim()))
        {
            query = query.Where(c => int.Parse(c.prepayment) <= int.Parse(txtPrepaymentFrom.Value) && int.Parse(c.prepayment) >= int.Parse(txtPrepaymentTo.Value));
        }

        if (!string.IsNullOrEmpty(txtPriceFrom.Value.Trim()))
        {
            query = query.Where(c => int.Parse(c.price) <= int.Parse(txtPriceFrom.Value));
        }
        if (!string.IsNullOrEmpty(txtPriceTo.Value.Trim()))
        {
            query = query.Where(c => int.Parse(c.price) >= int.Parse(txtPriceTo.Value));
        }
        if (!string.IsNullOrEmpty(txtPriceFrom.Value.Trim()) && !string.IsNullOrEmpty(txtPriceTo.Value.Trim()))
        {
            query = query.Where(c => int.Parse(c.price) <= int.Parse(txtPriceFrom.Value) && int.Parse(c.price) >= int.Parse(txtPriceTo.Value));
        }

        if (!string.IsNullOrEmpty(txtFloor.Value.Trim()))
        {
            query = query.Where(c => c.eFloor == short.Parse(txtFloor.Value));
        }
        if (chbExchange.Checked)
        {
            query = query.Where(c => c.exchange == true);
        }

        var final = query.Select(c => new { c.esId,c.owId, c.City.cityName, c.EstateShape.eshName, c.EstateType.ETName, c.owner.owFname, c.owner.owLname, c.esSize, c.prepayment, c.price });
        return Special.LINQResultToDataTable(final.ToList());
}

此功能运行良好，但现在我想更多地从EstateEquipment和EstateFacility中添加一些parameres。
如您在ORM中所见，Estate和EstateEquipment之间的关系（也是Estate和EstateFacility）是one to many。
现在我想让用户可以搜索cityId = 1，size around 400m中的遗产，例如，eqId = 1 and 2中的EstateEquipment和fId = 1 and 2中的{来自EstateFacility。

这就是我尝试处理最后一部分的方式。

foreach (ListItem item in cblEquipment.Items)
{
    if (item.Selected)
    {
        eq = true;
    }
}
if(eq)
{
    var eqQuery = ctx.EstateEquipments.AsQueryable();
    foreach (ListItem item in cblEquipment.Items)
    {
        if (item.Selected)
        {
            eqQuery = eqQuery.Where(c => c.eqId == int.Parse(item.Value.ToString()));
        }
    }
    var eqFinal = eqQuery.Select(c => new { c.Estate.esId, c.Estate.owner.owId, c.Estate.City.cityName, c.Estate.EstateShape.eshName, c.Estate.EstateType.ETName, c.Estate.owner.owFname, c.Estate.owner.owLname, c.Estate.esSize, c.Estate.prepayment, c.Estate.price });
    DataTable dtEq = Special.LINQResultToDataTable(eqFinal.ToList());
    if(dtEq.Rows.Count>0)
    {
        this.Build_search(dtEq);
    }
    else
    {
        msg = "No record found";
        sysMsg.Attributes["class"] = "";
        sysMsg.Attributes["class"] = "alert alert-warning";
    }
}

在这里，首先，我检查从列表中选择了哪种设备。然后根据选择的项目扩展查询。但是我不知道如何将这个新结果与最后一个结果甚至EstateFacility结果结合起来。
感谢您的帮助。

Answer 1

由于您的案子比较复杂，无法测试我的解决方案，我希望它至少可以为您指明正确的方向。

我会说尝试这样的事情：

    if (cblEquipment.Items.Any(item => item.Selected))
    {
        var selectedEquipmentIds = cblEquipment.Items.Where(item => item.Selected).Select(item => int.Parse(item.Value.ToString()));
        query = query.Where(c => ctx.EstateEquipments.Any(eq => eq.esId == c.esId && selectedEquipmentIds.Contains(eq.eqId)));
    }

这出现在var final ...之前的第一个代码段中。然后将不使用第二个片段，因此您在那里的错误处理也将需要移动...

在DBML中使用LINQ在多个联接表中使用多个搜索参数

1 个答案: