Question

我收到此错误

Cannot implicitly convert type 'System.Linq.IQueryable<AnonymousType#1>' to 'System.Linq.IQueryable<object>'

运行3.5 .net之前从未遇到此问题。不知道改变了什么。

错误发生在选择新{ITEMID = p.PRESSRELEASEID};

我已经尝试过，但仍然会遇到不同的转换错误。

StringBuilder textStr = new StringBuilder();

var years = (from ys in db.tblPressReleases orderby ys.prdate descending select ys.prdate.Year).Distinct();

ddlYear.DataSource = years;
ddlYear.DataBind();
ddlYear.Items.Insert(0, new ListItem("Year", ""));

IQueryable<object> pressreleases ;
DateTime startdate, enddate;

if (this.iFilterMonth != null && this.iFilterMonth > 0 && this.iFilterYear != null)
{
    startdate = new DateTime((int)this.iFilterYear, (int)this.iFilterMonth, 1);
    enddate = startdate.AddMonths(1);

    pressreleases = from p in db.tblPressReleases
                    where p.prdate.Date >= startdate.Date && p.prdate.Date < enddate.Date
                    orderby p.prdate descending
                    select new { ITEMID = p.PRESSRELEASEID };
}
else if (this.iFilterYear != null)
{
    startdate = new DateTime((int)this.iFilterYear, 1, 1);
    enddate = new DateTime((int)this.iFilterYear + 1, 1, 1);

    pressreleases = from p in db.tblPressReleases
                    where p.prdate.Date >= startdate.Date && p.prdate.Date < enddate.Date
                    orderby p.prdate descending
                    select new { ITEMID = p.PRESSRELEASEID };
}
else
{
    pressreleases = (from p in db.tblPressReleases
                    orderby p.prdate descending
                    select new { ITEMID = p.PRESSRELEASEID }).Take(15);
}

dlDisplay.DataSourceID = "";
dlDisplay.DataSource = pressreleases;
dlDisplay.Visible = true;
dlDisplay.DataBind();

Answer 1

三个独立选项：

完全抛弃匿名类型。您只有一个值，为什么不使用select p.PRESSRELEASEID？

转换为select子句：

select (object) new { ITEMID = p.PRESSRELEASEID }

使用var声明变量，提供一个虚拟示例：

var pressreleases = new[] { new { ITEMID = "" } }.ToQueryable();

顺便说一句，我强烈建议重新考虑你的命名 - 无论是在VERYSHOUTY名字还是非常安静的名字方面;更常规的名称是pressReleases（对于局部变量）和PressReleaseID（对于属性）。

如何转换[AnonymousType＃1]或预先定义它？

1 个答案: