我正在为当地学校开发一个小项目，我几乎可以称之为编程中的新手。 我试图在日历中检索用户选择的日期以保存到单独的数据库。我有一个实体框架模型（.edmx）来链接我需要的Visual Studio中的表。 这是我到目前为止所得到的：
ASP.net：
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<div class="main_banner">
</div>
<div class="main_container">
<div class="main_heading">
<h1 class="main_title">Projector Inspection</h1>
<p><a href="AddProjector.aspx">Add</a> new Projector</p>
</div>
<div class="info_container">
<div>
<asp:Label ID="RoomNolbl" runat="server" Text="Room No:"></asp:Label>
</div>
<div>
<asp:DropDownList ID="DropDownList1" runat="server" DataSourceID="Roomsdbo" DataTextField="Room_No" DataValueField="Room_No" AutoPostBack="True">
<asp:ListItem>---Select Room---</asp:ListItem>
</asp:DropDownList>
<asp:SqlDataSource ID="Roomsdbo" runat="server" ConnectionString="<%$ ConnectionStrings:iPadLoanConnectionString2 %>" SelectCommand="SELECT [Room_No] FROM [tblRooms]"></asp:SqlDataSource>
</div>
<div>
<asp:Label ID="Datelbl" runat="server" Text="Date Checked:"></asp:Label>
</div>
<div>
<asp:Calendar ID="Calendar1" runat="server" BackColor="White" BorderColor="White" BorderWidth="1px" Font-Names="Verdana" Font-Size="9pt" ForeColor="Black" Height="190px" NextPrevFormat="FullMonth" Width="350px" OnSelectionChanged="Calendar1_SelectionChanged1" DayNameFormat="Shortest">
<DayHeaderStyle Font-Bold="True" Font-Size="8pt" />
<NextPrevStyle Font-Bold="True" Font-Size="8pt" ForeColor="#333333" VerticalAlign="Bottom" />
<OtherMonthDayStyle ForeColor="#999999" />
<SelectedDayStyle BackColor="#333399" ForeColor="White" />
<TitleStyle BackColor="White" BorderColor="#ae1022" BorderWidth="4px" Font-Bold="True" Font-Size="12pt" ForeColor="#ae1022" />
<TodayDayStyle BackColor="#CCCCCC" />
</asp:Calendar>
<asp:TextBox ID="Calendartxt" runat="server" ReadOnly="True"></asp:TextBox>
</div>
<div class ="info_container_task">
<h3>Task carried</h3>
<div>
<asp:Label ID="CheckBoxFilterlbl" runat="server" Text="Filter Cleaning:"></asp:Label>
<asp:CheckBox ID="CheckBoxFilter" runat="server" OnCheckedChanged="CheckBoxFilter_CheckedChanged" AutoPostBack="true" />
</div>
<div>
<asp:Label ID="CheckBoxBulblbl" runat="server" Text="Bulb Replacement:"></asp:Label>
<asp:CheckBox ID="CheckBoxBulb" runat="server" OnCheckedChanged="CheckBoxBulb_CheckedChanged" AutoPostBack="true"/>
</div>
<div>
<asp:Button ID="ButtonSubmit" runat="server" Text="Submit" OnClick="ButtonSubmit_Click" />
</div>
</div>
<div>
<asp:Label ID="HourCountBulblbl" runat="server" Text="Bulb Hours:"></asp:Label>
</div>
<div>
<asp:TextBox ID="HourBulbtxt" runat="server" ></asp:TextBox>
</div>
<div>
<asp:Label ID="FilterHourlbl" runat="server" Text="Filter Hours:"></asp:Label>
</div>
<div>
<asp:TextBox ID="FilterHourtxt" runat="server" ></asp:TextBox>
</div>
<div>
<asp:Label ID="Commentslbl" runat="server" Text="Additional Comments:" ></asp:Label>
</div>
<div>
<textarea id="Commentstxt" cols="20" rows="2" ></textarea> </div>
</div>
</div>
<div class="sub_container">
<h2>Additional Information</h2>
<div class="Tbl_Projectorinfo">
<div class="projectorGrid">
<asp:GridView ID="projectorinfo" runat="server" AutoGenerateColumns="False" CellPadding="4" DataSourceID="linkprojectorsdbo" ForeColor="#333333" GridLines="None" DataKeyNames="Model_No">
<AlternatingRowStyle BackColor="White" ForeColor="#284775" />
<Columns>
<asp:BoundField DataField="Current_Hours" HeaderText="Current_Hours" SortExpression="Current_Hours" />
<asp:BoundField DataField="Last_Replacement_Date" HeaderText="Last_Replacement_Date" SortExpression="Last_Replacement_Date" />
<asp:BoundField DataField="Last_Cleaned" HeaderText="Last_Cleaned" SortExpression="Last_Cleaned" />
</Columns>
<EditRowStyle BackColor="#999999" />
<FooterStyle BackColor="#ae1022" Font-Bold="True" ForeColor="White" />
<HeaderStyle BackColor="#ae1022" Font-Bold="True" ForeColor="White" />
<PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
<RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
<SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
<SortedAscendingCellStyle BackColor="#E9E7E2" />
<SortedAscendingHeaderStyle BackColor="#506C8C" />
<SortedDescendingCellStyle BackColor="#FFFDF8" />
<SortedDescendingHeaderStyle BackColor="#6F8DAE" />
</asp:GridView>
</div>
<asp:SqlDataSource ID="linkprojectorsdbo" runat="server" ConnectionString="<%$ ConnectionStrings:iPadLoanConnectionString %>" SelectCommand="SELECT [Model_No], [Current_Hours], [Last_Replacement_Date], [Last_Cleaned] FROM [tblProjectors] WHERE ([Room_No] = @Room_No)">
<SelectParameters>
<asp:ControlParameter ControlID="DropDownList1" Name="Room_No" PropertyName="SelectedValue" Type="String" />
</SelectParameters>
</asp:SqlDataSource>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataSourceID="tblModels" CellPadding="4" ForeColor="#333333" GridLines="None">
<AlternatingRowStyle BackColor="White" ForeColor="#284775" />
<Columns>
<asp:BoundField DataField="Manufacturer" HeaderText="Manufacturer" SortExpression="Manufacturer" />
<asp:BoundField DataField="Model_Name" HeaderText="Model" SortExpression="Model_Name" />
<asp:BoundField DataField="Min_Hours" HeaderText="MinHours" SortExpression="Min_Hours" />
<asp:BoundField DataField="Max_Hours" HeaderText="MaxHours" SortExpression="Max_Hours" />
</Columns>
<EditRowStyle BackColor="#999999" />
<FooterStyle BackColor="#ae1022" Font-Bold="True" ForeColor="White" />
<HeaderStyle BackColor="#ae1022" Font-Bold="True" ForeColor="White" />
<PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
<RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
<SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
<SortedAscendingCellStyle BackColor="#E9E7E2" />
<SortedAscendingHeaderStyle BackColor="#506C8C" />
<SortedDescendingCellStyle BackColor="#FFFDF8" />
<SortedDescendingHeaderStyle BackColor="#6F8DAE" />
</asp:GridView>
<asp:SqlDataSource ID="tblModels" runat="server" ConnectionString="<%$ ConnectionStrings:iPadLoanConnectionString %>" SelectCommand="SELECT [Manufacturer], [Model_Name], [Min_Hours], [Max_Hours] FROM [ProjectorsRoom2017] WHERE ([Room_No] = @Room_No)">
<SelectParameters>
<asp:ControlParameter ControlID="DropDownList1" Name="Room_No" PropertyName="SelectedValue" Type="String" />
</SelectParameters>
</asp:SqlDataSource>
</div>
</div>
.cs文件：
protected void ButtonSubmit_Click(object sender, EventArgs e)
{
tblProjector entry = new tblProjector();
entry.Last_Cleaned = Convert.ToDateTime(Calendartxt.Text);
iPadLoanEntities db = new iPadLoanEntities();
db.tblProjectors.Add(entry);
db.SaveChanges();
}
protected void Calendar1_SelectionChanged1(object sender, EventArgs e)
{
Calendartxt.Text = Calendar1.SelectedDate.ToShortDateString();
}
}
我经常收到错误消息，指出一个或多个实体的验证失败。错误也指向代码行：
db.SaveChanges();
我知道使用该代码我试图获取链接到日历的TextBox的信息以保存到数据库，但说实话，如果可能的话，直接从日历中保存它将是很好的。< / p>
如果有人能帮我说明如何实现这一目标，我将不胜感激。感谢