我如何转换[AnonymousType#1]或预定义它

本文关键字：AnonymousType#1 预定义 何转换 转换 | 更新日期: 2023-09-27 18:08:25

我得到这个错误

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

运行3.5 .net以前从未有过此问题。不确定修改了什么

错误发生在select new {ITEMID = p. pressreleaseid};

我已经试过了，但是一直得到不同的转换错误。

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();

我如何转换[AnonymousType#1]或预定义它

三个独立选项:

  • 完全放弃匿名类型。你只有一个值，所以为什么不使用select p.PRESSRELEASEID ?

  • 在select子句中强制转换:

    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();

作为题外话，我强烈建议重新考虑你的命名——无论是非常响亮的名字还是非常安静的名字;更常规的名称是pressReleases(用于局部变量)和PressReleaseID(用于属性)。

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