Question

我已经在ajax ModalpopupExtender中输入了一个下拉列表并从表中填充，然后我需要选择下拉列表选择项的ID？

myfile.aspx.cs string MyQuery = string.Format（“select table from table where colName ='{0}'”，dropdown.SelectedItem.Text）; SqlConnection con = DatabaseConnection.CreateConnection（）; SqlCommand cmd = new SqlCommand（MyQuery，con）; 字符串MyId; MyId = cmd.ExecuteScalar（）as string;

//我也试过这个 int id = dropdownList.DataValueField;

请回复我，如何在执行select查询后以及填充数据表或数据集时从表中获取id？谢谢aloooot。

Answer 1

这不是我的原始代码段。当我在messagebox中显示MyId变量时它是空的，并且在插入查询之后它说插入语句与外键约束冲突。这意味着代码不会获取我需要放在子表中的外键中的id。

这是我的代码隐藏文件 string MyQuery = string.Format（＆＃34;从District中选择DistrictId，其中DistrictName =＆＃39; {0}＆＃39;＆＃34;，ddlAddDistrict.SelectedItem.Text）; SqlConnection con = DatabaseConnection.CreateConnection（）; SqlCommand cmd = new SqlCommand（MyQuery，con）; 字符串MyId; MyId = cmd.ExecuteScalar（）as string; //Response.Write("alert('" + ddlAddDistrict.SelectedItem.Text +＆＃34;＆＃39;）＆＃34;）; Response.Write（＆＃34; alert（＆＃39;＆＃34; + MyId +＆＃34;＆＃39;）＆＃34;）; string insert =＆＃34;插入PoliceStation值（＆＃39;＆＃34; + MyId +＆＃34;＆＃39;＆＃39;＆＃34; + policeStation +＆＃34;＆＃39; ;）＆＃34 ;; InsertIntoDB.InsertQuery（插入）; if（InsertIntoDB.count＆gt; 0） { Response.Write（＆＃34; alert（＆＃39;记录添加成功＆＃39;）＆＃34;）; InsertIntoDB.count = 0; } 其他{ Response.Write（＆＃34; alert（＆＃39;错误：记录未添加＆＃39;）＆＃34;）;

    }
this is my  .aspx file

＆lt;％ - ============================派出所的模态弹出窗口========= ============= - ％＆gt;

                <AddNewPopup:ModalPopupExtender ID="mp1" runat="server" PopupControlID="PanlAddNewPS" TargetControlID="lbtnAddNewPS"
                    CancelControlID="btncanceladdNewPs" BackgroundCssClass="Background" OnLoad="mp1_Load">
                </AddNewPopup:ModalPopupExtender>

                <asp:Panel ID="PanlAddNewPS" runat="server" CssClass="PopupPoliceStation panel-info" align="center" Style="display: none">
                    <%--<a style="width: 600px; height: 200px;" id="irm1" src="PSDialog.aspx" runat="server"></a>--%>
                    <div class="panel-heading">
                        <div class="panel-title">Add New Police Station</div>
                    </div>
                    <br />
                    <div class="row">
                        <div class="col-sm-12">
                            <div class="form-group">

                                <asp:Label runat="server" Text="Add District" Font-Bold="true" ID="Label2" CssClass="col-sm-4 control-label" ></asp:Label>
                                <div class="col-sm-8">
                                    <asp:DropDownList runat="server" ID="ddlAddDistrict" CssClass="form-control" MaxLength="20" OnSelectedIndexChanged="ddlAddDistrict_SelectedIndexChanged"></asp:DropDownList>

                                     <asp:RequiredFieldValidator ID="RequiredFieldValidator9" runat="server" ControlToValidate="ddlAddDistrict" ErrorMessage="Select district" Font-Size="Small" ForeColor="Red" ValidationGroup="ValidateAddNewPoliceSation" InitialValue="Select New District"  ></asp:RequiredFieldValidator>
                                </div> <br /><br />

                                <asp:Label runat="server" Text="Police Station" Font-Bold="true" ID="lblPSName" CssClass="col-sm-4 control-label" ></asp:Label>
                                <div class="col-sm-8">
                                    <asp:TextBox runat="server" ID="txtAddPSName" CssClass="form-control" MaxLength="15"></asp:TextBox>
                                     <asp:RequiredFieldValidator ID="RequiredFieldValidator8" runat="server" ControlToValidate="txtAddPSName" ErrorMessage="Required" Font-Size="Small" ForeColor="Red" ValidationGroup="ValidateAddNewPoliceSation" ></asp:RequiredFieldValidator>
                                </div> <br /><br />

                            </div>
                        </div>
                    </div>
                    <asp:Button runat="server" CssClass="btn btn-success" ID="btnAddNewPS" Text="Add" ValidationGroup="ValidateAddNewPoliceSation" OnClick="btnAddNewPS_Click" />
                    <asp:Button CssClass="btn btn-info" ID="btncanceladdNewPs" runat="server" Text="Cancel" CausesValidation="false" />
                </asp:Panel>

我正在尝试根据下拉列表选择项目获取ID

1 个答案: