asp.net - 使用 linq 解决 DateTime 错误

Question

我怎样才能用 Linq 做到这一点？我试过没有成功

protected void Calendar1_SelectionChanged(object sender, EventArgs e)
{
    DataView view = socialEvents.DefaultView;
    view.RowFilter = String.Format(
                      "Date >= #{0}# AND Date < #{1}#",
                      Calendar1.SelectedDate.ToShortDateString(),
                      Calendar1.SelectedDate.AddDays(1).ToShortDateString()
                   );

    if (view.Count > 0)
    {
        DataGrid1.Visible = true;
        DataGrid1.DataSource = view;
        DataGrid1.DataBind();
    }
    else
    {
        DataGrid1.Visible = false;
    }
}

我试试这个，但它不起作用

用户代码未处理 SyntaxErrorException 表达式包含无效名称：[]。

再试一次

var rows =  socialEvents.Rows.Cast<DataRow>()
            .Where(r => (DateTime)r["Date"] >= Calendar1.SelectedDate.Date &&
                        (DateTime)r["Date"] <= Calendar1.SelectedDate.AddDays(1))
              .ToArray();
view.RowFilter = rows.ToString();  

Answer 1

以下是您应该如何使用RowFilter：

view.RowFilter = String.Format(
                  "Date >= #{0}# AND Date < #{1}#",
                  Calendar1.SelectedDate.ToString("MM/dd/yyyy"),
                  Calendar1.SelectedDate.AddDays(1).ToString("MM/dd/yyyy"));

或者使用 LINQ

var table = (from r in socialEvents.AsEnumerable()
             where r.Field<DateTime>("Date") >= Calendar1.SelectedDate.Date
                   r.Field<DateTime>("Date") <= Calendar1.SelectedDate.AddDays(1)
             select r).CopyToDataTable();  

if (table.Rows.Count > 0)
{
    DataGrid1.Visible = true;
    DataGrid1.DataSource = table;
    DataGrid1.DataBind();
}
else
{
    DataGrid1.Visible = false;
}