C# 下拉列表选择值

这可能看起来很琐碎，我曾经知道如何做到这一点，但由于某种原因，这次我似乎无法集中注意力：

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

我有两张桌子：

Hotel

和

HotelRooms

Hotel

表包含

HotelID

和其他酒店详细信息，

HotelID

可在

HotelRooms

中找到，每个房间类型都有描述。 一家酒店可以有多种房间类型

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

我有一个

DropDownList

，其中包含

HotelID

和

roomid

HotelID

来自会话变量

HotelID

是

DropDownList的值；但列表显示的是

RoomType

。
当选中

Roomtypes

时，我想显示一个

GridView`显示酒店房间的详细信息，如描述、价格等

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

我不能这样做，因为我的DropDownList的值是

HotelID

，它映射到

会话ID

。我如何从下拉列表的选定值中获取酒店房间详细信息

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

更新：

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

Gridview的代码：

        string intResortID = Request.QueryString("intResortID ")
        string strRoomType = DropDownList2.SelectedValue;
        string connStr = ConfigurationManager.ConnectionStrings["bdsConnectionString"].ConnectionString;
        SqlConnection Con = new SqlConnection(connStr);
        SqlDataAdapter sdr = new SqlDataAdapter("SELECT TOP (100) PERCENT tblAvail.dtm, tblResortsRooms.strRoomType, tblResortsRooms.strDescription, tblAvail.intQty, tblAvail.curPrice, tblAvail.intResortID, tblResortsRooms.intWSCode FROM tblAvailable INNER JOIN tblResortsRooms ON tblAvail.intResortID = tblResortsRooms.intResortID AND tblAvail.strRoomType = tblResortsRooms.strRoomType WHERE (tblResortsRooms.curRecRate > 0) AND (tblAvail.intResortID = @intResortID) AND (tblAvail.strRoomType = @strRoomType) AND (tblAvailable.dtm >= { fn CURDATE() }) ORDER BY tblResortsRooms.strRoomType",Con);
        SqlParameter ResID = new SqlParameter("@intResortID", intResortID);
        SqlParameter RoomType = new SqlParameter("@strRoomType", strRoomType);
        sdr.SelectCommand.Parameters.Add(ResID);
        sdr.SelectCommand.Parameters.Add(RoomType);

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

试试dropdownlist的

SelectedItem.Text

。

试试dropdownlist的

SelectedItem.Text

。

听起来您需要在HotelRooms表中添加一个新的ID（主键），它唯一地标识每个房间。如果有，您可以使用该值作为下拉列表的值，问题就会消失。

听起来您需要在HotelRooms表中添加一个新的ID（主键），以唯一地标识每个房间。如果您有，您可以使用该值作为下拉列表的值，问题就会消失。

'DropDownList1.SelectedValue'应该为您提供

@intrestorid

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

“DropDownList2.SelectedValue”应该为您提供

@stroomtype

的值

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

DropDownList2\u SelectedIndexChanged

应通过某种方式（如a）运行查询。
填充的数据表应该绑定到GridView

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

在

DropDownList2\u SelectedIndexChanged

方法中尝试以下操作：

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

string intResortID = Request.QueryString("intResortID ");
string strRoomType = DropDownList2.SelectedValue;
string connStr = ConfigurationManager.ConnectionStrings["bdsConnectionString"].ConnectionString;
SqlConnection Con = new SqlConnection(connStr);
SqlDataAdapter sdr = new SqlDataAdapter("SELECT TOP (100) PERCENT tblAvail.dtm, tblResortsRooms.strRoomType, tblResortsRooms.strDescription, tblAvail.intQty, tblAvail.curPrice, tblAvail.intResortID, tblResortsRooms.intWSCode FROM tblAvailable INNER JOIN tblResortsRooms ON tblAvail.intResortID = tblResortsRooms.intResortID AND tblAvail.strRoomType = tblResortsRooms.strRoomType WHERE (tblResortsRooms.curRecRate > 0) AND (tblAvail.intResortID = @intResortID) AND (tblAvail.strRoomType = @strRoomType) AND (tblAvailable.dtm >= { fn CURDATE() }) ORDER BY tblResortsRooms.strRoomType", Con);
SqlParameter ResID = new SqlParameter("@intResortID", intResortID);
SqlParameter RoomType = new SqlParameter("@strRoomType", strRoomType);
sdr.SelectCommand.Parameters.Add(ResID);
sdr.SelectCommand.Parameters.Add(RoomType);
DataTable results = new DataTable();

sdr.Fill(results);

resultsGridView.DataSource = results;   //Assuming resultsGridView is the name of the GridView on your ASPX page.
resultsGridView.DataBind();

---

“DropDownList1.SelectedValue”应该为您提供

@intrestorid

的值
“DropDownList2.SelectedValue”应该为您提供

@stroomtype

的值

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

DropDownList2\u SelectedIndexChanged

应通过某种方式（如a）运行查询。
填充的数据表应该绑定到GridView

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

在

DropDownList2\u SelectedIndexChanged

方法中尝试以下操作：

      <asp:DropDownList ID="DropDownList2" runat="server" 
        DataSourceID="SqlDataSource2" DataTextField="strRoomType" 
        DataValueField="intResortID" 
        onselectedindexchanged="DropDownList2_SelectedIndexChanged" 
        AutoPostBack="True">
    </asp:DropDownList>
    <asp:SqlDataSource ID="SqlDataSource2" runat="server" 
       SelectCommand="SELECT [intResortID], [strRoomType] FROM [tblResortsRooms] WHERE ([intResortID] = @intResortID)">
        <SelectParameters>
            <asp:ControlParameter ControlID="DropDownList1" Name="intResortID" 
                PropertyName="SelectedValue" Type="Int32" />
        </SelectParameters>
    </asp:SqlDataSource>

string intResortID = Request.QueryString("intResortID ");
string strRoomType = DropDownList2.SelectedValue;
string connStr = ConfigurationManager.ConnectionStrings["bdsConnectionString"].ConnectionString;
SqlConnection Con = new SqlConnection(connStr);
SqlDataAdapter sdr = new SqlDataAdapter("SELECT TOP (100) PERCENT tblAvail.dtm, tblResortsRooms.strRoomType, tblResortsRooms.strDescription, tblAvail.intQty, tblAvail.curPrice, tblAvail.intResortID, tblResortsRooms.intWSCode FROM tblAvailable INNER JOIN tblResortsRooms ON tblAvail.intResortID = tblResortsRooms.intResortID AND tblAvail.strRoomType = tblResortsRooms.strRoomType WHERE (tblResortsRooms.curRecRate > 0) AND (tblAvail.intResortID = @intResortID) AND (tblAvail.strRoomType = @strRoomType) AND (tblAvailable.dtm >= { fn CURDATE() }) ORDER BY tblResortsRooms.strRoomType", Con);
SqlParameter ResID = new SqlParameter("@intResortID", intResortID);
SqlParameter RoomType = new SqlParameter("@strRoomType", strRoomType);
sdr.SelectCommand.Parameters.Add(ResID);
sdr.SelectCommand.Parameters.Add(RoomType);
DataTable results = new DataTable();

sdr.Fill(results);

resultsGridView.DataSource = results;   //Assuming resultsGridView is the name of the GridView on your ASPX page.
resultsGridView.DataBind();

---

---

你能至少给我们看一些代码吗^^您在哪里以及如何填写您的下拉列表？你能展示一下吗？再次更新，请看上面我想你搞错了。拥有具有相同值的DataValueField有什么意义？如果您的DataTextField是RoomID，您是否向用户显示房间Id的列表？那不好。你能把你正在使用的表格和列名一起发布吗？不知道相同的值是什么意思，但已经用dropdownlist的代码更新了我上面的问题。你能至少给我们展示一些代码吗^^您在哪里以及如何填写您的下拉列表？你能展示一下吗？再次更新，请看上面我想你搞错了。拥有具有相同值的DataValueField有什么意义？如果您的DataTextField是RoomID，您是否向用户显示房间Id的列表？那不好。您可以发布您正在使用的表以及列名吗？不确定相同的值是什么意思，但已经用dropdownlistI get error object reference的代码更新了我上面的问题没有设置为object的实例下拉列表中有哪些字段？HotelID作为DataValueField，RoomID作为DataTextField？那么为了测试，您是否在DropDownList的OnSelectedIndexChange事件上运行代码？您应该能够从事件的发送方访问DropDownList属性。是的，我正在DropDownList的selectedindexchange事件中运行代码。这似乎是您在此阶段遇到的唯一问题。您可以发布您试图在事件中检索值的位置的代码吗？I get error object reference未设置为对象的实例下拉列表中有哪些字段？HotelID作为DataValueField，RoomID作为DataTextField？那么为了测试，您是否在DropDownList的OnSelectedIndexChange事件上运行代码？您应该能够从事件的发送方访问DropDownList属性。是的，我正在DropDownList的selectedindexchange事件中运行代码。这似乎是您在此阶段遇到的唯一问题。您可以发布您试图在事件中检索值的位置的代码吗？@John My HotelRoom ID是HotelRoom表的主键和ID，但因为它是My hotelID，是数据字段值，而不是hotel Room ID，我无法在gridview中显示任何内容，因为没有roomtype来代替复合主键，您可以添加单个id字段作为新的主键，并将其用于值？这取决于用户先选择酒店，然后在下拉列表中填入该酒店的房间。我不明白你的意思，我已经尝试了一个dropdownlist用于酒店列表，另一个dropdownlist用于房间列表，但是当我选择roomtype时，GridViews没有发生任何变化。据我所知，没有唯一标识房间的id。唯一id来自HotelID和RoomID的组合？这意味着您无法从下拉列表加载房间数据，因为下拉列表只有一个值字段。您需要做的是将另一个字段添加到房间表中，这是一个标识字段，并将其作为主键。然后将其用作下拉列表中的值字段。所以你有一个酒店列表，当你选择的时候