c# - 错误 :Cannot implicitly convert type 'System.DateTime' to 'System.Data.Common.DbParameter'

Question

我在后面的代码中遇到错误，我不确定下一步该怎么做

前端(asp.net)中的代码是

<asp:SqlDataSource ID="SqlDataSource2" runat="server" 
                ConnectionString="<%$ ConnectionStrings:LicensingConnectionString %>" 



                SelectCommand="SELECT [School Name], [School City], [School State], LoginName, [Current Sales], Commission, [Pay Period start date], [Pay Period End date] FROM commissions WHERE ([Pay Period start date] &gt;= @Txt_selected_start_date) AND ([Pay Period End date] &lt;= @Txt_selected_end_date) AND (LoginName = 'mervinj@uw.edu') " 
                OnSelecting="SqlDataSource2_Selecting"
                >
                <SelectParameters>
                    <asp:parameter  
                        Name="Txt_selected_start_date" Type="DateTime" />
                    <asp:Parameter Name="Txt_selected_end_date"  Type="DateTime" />
                </SelectParameters>
            </asp:SqlDataSource>



<asp:PlaceHolder ID="pnlwithdates" runat="server" Visible="false"> 
<div style="padding: 0 200px 0 200px">
<br /><br />
Start Date: <asp:TextBox ID="TxtDatepicker_start" runat="server" Width = 125px >
      </asp:TextBox>

      &nbsp;&nbsp;End Date: <asp:TextBox ID="TxtDatepicker_end" runat="server" Width = 125px >
      </asp:TextBox>
      &nbsp;&nbsp;&nbsp;&nbsp;<asp:Button ID="Button_daterecords" runat="server"  Text="Show records"  OnClick ="SQLDisplay_Date_records" /><br />
<br /><br />

而后端的代码是

protected void SqlDataSource2_Selecting(object sender, SqlDataSourceSelectingEventArgs e) { e.Command.Parameters["@username"].Value = HttpContext.Current.User.Identity.Name; e.Command.Parameters["@Txt_selected_start_date"] = DateTime.Parse(TxtDatepicker_start.Text);

    }

粗体代码是抛出错误的行。

我该如何解决这个问题，任何输入都会很好。

谢谢

Answer 1

你设置错了，应该是:

e.Command.Parameters["@Txt_selected_start_date"].Value = DateTime.Parse(TxtDatepicker_start.Text);

请注意您的代码中缺少的 .Value。您正在尝试将 DateTime 分配给 DbParameter。