C# DropDownList 仅在服务器上表现奇怪，而不是本地答案

【问题标题】：C# DropDownList behaving strangely only on server, not localC# DropDownList 仅在服务器上表现奇怪，而不是本地
【发布时间】：2015-11-23 03:49:47
【问题描述】：

我有一个带有一些文本输入字段和 3 个组合框的表单，以及一个提交按钮，用于将表单的数据保存到数据库的表中。所以当我点击提交按钮的时候，经过一番调试，我发现在点击的那一刻，comboboxes没有选中值，从而带来错误和异常，显然没有将数据保存到数据库中。但不仅如此，此外，在单击提交按钮后，组合框会丢失所有值，并且填充它们的完整列表消失，就好像它们没有被初始化一样。

所有这一切的可悲部分（因为我知道我可以再查看一下我的代码）是，当我在我的 ASP.NET Visual 上使用完全相同的代码（相同的 dll 和所有内容）执行完全相同的操作时Studio 服务器（在我的本地计算机上）一切正常，因此我正在写入同一个远程数据库，并且在单击提交按钮后数据保存到数据库中，并且表单与所有组合框保持正常，就像单击之前一样。

为什么这只发生在服务器上？为什么在本地可以毫无问题地读写数据库？

我认为这可能与我的 Page_Load 方法上的 PostBack 相关（我在其中初始化组合框，但前提是它不是 PostBack）...所以这可能是与 IIS 服务器如何工作有关的问题使用可能与本地 ASP.NET 服务器不同的 PostBacks？

编辑我正在添加表单的 HTML 代码

<form id="form1" runat="server">    

<div class="popup" style="border: 1px solid #000; width: 600px;">
    <table style="height: 148px; width: 584px">
        <tr>
            <td class="style1">
                <table>
                    <tr>
                        <td>
                            <abbr title="El N° de Folio le será otorgado luego de haber guardado la necesidad."><asp:Label ID="Labe" runat="server" Text="Folio *" class="innerControl"></asp:Label></abbr>
                        </td>
                        <td colspan="2">
                            <abbr title="El N° de Folio le será otorgado luego de haber guardado la necesidad."><asp:TextBox ID="folTB" runat="server" Width="70px" class="innerControl" Enabled="false"></asp:TextBox></abbr>
                        </td>
                        <td>
                            <asp:Label ID="Label4" runat="server" Text="Fecha" class="innerControl"></asp:Label>
                        </td>
                        <td colspan="3">
                            <asp:TextBox ID="fecTB" runat="server" Width="100px" class="innerControl" Enabled="false"></asp:TextBox>
                            <asp:CalendarExtender  ID="TextBox1_CalendarExtender" runat="server" 
                                Enabled="True" TargetControlID="fecTB" DefaultView="Years" PopupButtonID="calBTN"></asp:CalendarExtender>
                            <asp:FilteredTextBoxExtender ID="FilteredTextBoxExtender1" runat="server" 
                                FilterType="Numbers, Custom" ValidChars="-" TargetControlID="fecTB">
                                </asp:FilteredTextBoxExtender>
                            <asp:ScriptManager ID="ScriptManager1" runat="server" 
                                EnableScriptGlobalization="True">
                            </asp:ScriptManager>
                        </td>
                    </tr>
                    <tr>
                        <td style="padding-right: 20px;">
                            <asp:Label ID="Label7" runat="server" Text="Beneficiarios" class="innerControl"></asp:Label>
                        </td>
                        <td style="padding-right: 20px;" colspan="2">
                            <asp:TextBox ID="benTB" runat="server" class="innerControl" Width="70px" Text="0" Enabled="false"></asp:TextBox>
                            <asp:FilteredTextBoxExtender ID="FilteredTextBoxExtender3" runat="server" 
                                FilterType="Numbers" TargetControlID="benTB">
                            </asp:FilteredTextBoxExtender>
                        </td>
                        <td style="padding-right: 20px;">
                            <asp:Label ID="Label2" runat="server" Text="Intendencia" class="innerControl"></asp:Label>
                        </td>
                        <td colspan="3">
                            <asp:DropDownList ID="intDDL" runat="server" class="innerControl" Width="270px">
                            </asp:DropDownList>
                        </td>
                    </tr>
                    <tr>
                        <td>
                            <asp:Label ID="Label9" runat="server" Text="Mes / Año" class="innerControl"></asp:Label>
                        </td>
                        <td>
                            <asp:DropDownList ID="mesDDL" runat="server" class="innerControl">
                            </asp:DropDownList>
                        </td>
                        <td>
                        /
                        </td>
                        <td>
                            <asp:DropDownList ID="anoDDL" runat="server" class="innerControl">
                            </asp:DropDownList>
                        </td>
                        <td style="width: 50px;">
                            <asp:Label ID="Label1" runat="server" Text="_________" class="innerControl" ForeColor="White"></asp:Label>
                        </td>
                        <td>
                            <asp:Label ID="Label10" runat="server" Text="Meses" class="innerControl"></asp:Label>
                        </td>
                        <td>
                            <asp:TextBox ID="mesesTB" runat="server" Width="77px" class="innerControl" 
                                Height="23px"></asp:TextBox>
                            <asp:FilteredTextBoxExtender ID="TBExtender" runat="server" 
                                FilterType="Numbers" TargetControlID="mesesTB">
                            </asp:FilteredTextBoxExtender>
                        </td>
                    </tr>                        
                </table>                    
            </td>
        </tr>
    </table>
</div>

<br />
<asp:Label runat="server" Text="Características del Requerimiento:" class="popup"></asp:Label>

<br />
<div class="popup" style="border: 1px solid #000; width: 600px;">
    <table style="height: 100px; width: 584px">
        <tr>
            <td class="style1">
                <table>
                    <tr>
                        <td>
                            <asp:Label ID="Label3" runat="server" Text="Población:" class="innerControl"></asp:Label>
                        </td>
                        <td colspan="2">
                            <asp:TextBox ID="pobTB" runat="server" Width="70px" class="innerControl"></asp:TextBox>
                        </td>                            
                        <td>
                            <asp:Label ID="Label5" runat="server" Text="Fundamentación:" class="innerControl"></asp:Label>
                        </td>
                        <td rowspan="3">
                            <asp:TextBox ID="fundTB" runat="server" Width="221px" class="innerControl" 
                                TextMode="MultiLine" Rows="7" Columns="35"></asp:TextBox>
                        </td>
                    </tr>
                    <tr>
                        <td style="padding-right: 20px;">
                            <asp:Label ID="Label6" runat="server" Text="Tasa Desempleo:" class="innerControl"></asp:Label>
                        </td>
                        <td style="padding-right: 20px;">
                            <asp:TextBox ID="empTB" runat="server" class="innerControl" Width="70px" ></asp:TextBox>
                            <asp:FilteredTextBoxExtender ID="FilteredTextBoxExtender2" runat="server" 
                                FilterType="Numbers, Custom" ValidChars=".," TargetControlID="empTB">
                                </asp:FilteredTextBoxExtender>                                
                        </td>
                        <td>
                            %
                        </td>
                    </tr>
                    <tr>
                        <td style="padding-right: 20px;">
                            <asp:Label ID="Label8" runat="server" Text="Tasa Pobreza:" class="innerControl"></asp:Label>
                        </td>
                        <td style="padding-right: 20px;">
                            <asp:TextBox ID="pobrTB" runat="server" class="innerControl" Width="70px" ></asp:TextBox>
                            <asp:FilteredTextBoxExtender ID="FilteredTextBoxExtender4" runat="server" 
                                FilterType="Numbers, Custom" ValidChars=".," TargetControlID="pobrTB">
                                </asp:FilteredTextBoxExtender>
                        </td>
                        <td>
                            %
                        </td>
                    </tr>
                </table>
            </td>
        </tr>
    </table>
</div>
<div class="popup" style="width: 601px;">
    <table>
        <tr>
            <td align="center" colspan="6" class="style2">
                <asp:Button ID="guardarNecesBTN" Text="Guardar" style="width: 110px;" 
                    runat="server" onclick="guardarNecesBTN_Click" Visible="true"/>
                <asp:Button ID="cerrarModBTN" Text="Cerrar" style="width: 110px;" 
                    runat="server" onclick="closePopUp" Visible="false"/>
            </td>
        </tr>
        <tr>
            <td class="style2">
                <asp:Label ID="Test" Text="" runat="server"></asp:Label>
            </td>
        </tr>
    </table>
</div>
</form>

这是 .cs 代码隐藏

public partial class nueva_necesidad : System.Web.UI.Page
{
    int fol = 0;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            loadMeses();
            loadAnos();
            loadIntendencias();
            String fec = DateTime.Today.Day.ToString();
            fec = fec + "-" + DateTime.Today.Month.ToString();
            fec = fec + "-" + DateTime.Today.Year.ToString();
            fecTB.Text = (fec);
        }
    }        

    protected void loadIntendencias()
    //Loads the intDDL with values taken from a DB table
    {
        intDDL.Items.Clear();
        ListItem newItem = null;

        List<entIntendencia> intList = new List<entIntendencia>();

        intList = boNeces.loadIntendencias(Convert.ToInt32(Session["reg_usu"].ToString()), Convert.ToInt32(Session["niv_usu"].ToString()));

        foreach (entIntendencia i in intList)
        {
            newItem = new ListItem();
            newItem.Text = i.nombre;
            newItem.Value = i.id_int.ToString();
            intDDL.Items.Add(newItem);
        }
    }

    protected void loadMeses()
    //Loads the mesDDL, pre-selecting the (current month + 2) from the DDL
    {
        DateTime d = DateTime.Today;
        int mesNum = d.Month;
        ListItem newItem = null;

        List<String> meses = new List<String>();
        meses.Add("Enero");
        meses.Add("Febrero");
        meses.Add("Marzo");
        meses.Add("Abril");
        meses.Add("Mayo");
        meses.Add("Junio");
        meses.Add("Julio");
        meses.Add("Agosto");
        meses.Add("Septiembre");
        meses.Add("Octubre");
        meses.Add("Noviembre");
        meses.Add("Diciembre");

        for (int i = 0; i <= 11; i++)
        {
            newItem = new ListItem();
            newItem.Text = meses[i];
            newItem.Value = (i + 1).ToString();
            mesDDL.Items.Add(newItem);
        }

        if (d.Month != 11 && d.Month != 12)
            mesDDL.SelectedIndex = mesNum + 1;
        else
        {
            if (d.Month == 11)
                mesDDL.SelectedIndex = 0;
            else
                mesDDL.SelectedIndex = 1;
        }   
    }

    protected void loadAnos()
    //Loads the anoDDL with a list of two: the current year and the next one.
    {
        anoDDL.Items.Clear();
        DateTime d = DateTime.Today;
        int ano = d.Year;
        ListItem newItem = null;

        List<int> list = new List<int>();

        list.Add(ano);
        list.Add(ano + 1);

        foreach (int an in list)
        {
            newItem = new ListItem();
            newItem.Text = an.ToString();
            newItem.Value = an.ToString();
            anoDDL.Items.Add(newItem);
        }
    }

    protected bool validaNecesidad(out int inten, out int meses, out int mes, out int ano, out int pob)
    //Validates the completion of the form's input fields.
    {
        inten = 0;
        meses = 0;
        mes = 0;
        ano = 0;
        pob = 0;

        Test.Text = intDDL.SelectedValue.ToString() + mesesTB.Text; //This line is intended to load the values of one of the comboboxes and one of the input textboxes onto a label called "Test" that's on the form itself, to check if they do have values or not, this is the first instruction that executes when the save button is clicked.

        if (!Int32.TryParse(intDDL.SelectedValue.ToString(), out inten))
        {
            Test.Text =  Test.Text + "Error en DDL intendencia";
            return false;
        }   
        if (inten <= 0)
        {
            Test.Text = Test.Text + "Error en DDL intendencia";
            return false;
        }

        if (!Int32.TryParse(mesesTB.Text, out meses))
        {
            Test.Text = Test.Text + "Error en TB meses";
            return false;
        }
        if (meses <= 0)
        {
            Test.Text = Test.Text + "Error en TB meses";
            return false;
        }

        if (!Int32.TryParse(mesDDL.SelectedValue, out mes))
        {
            Test.Text = Test.Text + "Error en DLL mes";
            return false;
        }
        if (mes <= 0)
        {
            Test.Text = Test.Text + "Error en DLL mes";
            return false;
        }

        if (!Int32.TryParse(anoDDL.SelectedValue, out ano))
        {
            Test.Text = Test.Text + "Error en DLL ano";
            return false;
        }
        if (ano <= 0)
        {
            Test.Text = Test.Text + "Error en DLL ano";
            return false;
        }

        if (!Int32.TryParse(pobTB.Text, out pob))
        {
            Test.Text = Test.Text + "Error en TB pob";
            return false;
        }
        if (pob <= 0)
        {
            Test.Text = Test.Text + "Error en TB pob";
            return false;
        }

        if (string.IsNullOrWhiteSpace(empTB.Text))
        {
            Test.Text = Test.Text + "Error en TB emp";
            return false;
        }

        if (string.IsNullOrWhiteSpace(pobrTB.Text))
        {
            Test.Text = Test.Text + "Error en TB pobr";
            return false;
        }

        if (string.IsNullOrWhiteSpace(fundTB.Text))
        {
            Test.Text = Test.Text + "Error en TB fund";
            return false;
        }
        return true;
    }

    protected void guardarNecesBTN_Click(object sender, EventArgs e)
    //Saves a new record on the NECESIDADES table.
    {
        int res = 0;            

        int inten = 0;
        int meses = 0;
        int mes = 0;
        int ano = 0;
        int pob = 0;

        if (validaNecesidad(out inten, out meses, out mes, out ano, out pob))
        {
            res = boNeces.saveNeces(inten, meses, mes, ano, pob, empTB.Text, pobrTB.Text, fundTB.Text, Session["log_usu"].ToString());
            if (res != 0)
            {
                Test.Text = Test.Text + "Folio creado correctamente con el N° " + res + ".";
                Test.ForeColor = System.Drawing.Color.Green;
                guardarNecesBTN.Visible = false;
                cerrarModBTN.Visible = true;
                intDDL.SelectedIndex = 0;
                loadMeses(); loadAnos();
                empTB.Text = ""; pobTB.Text = ""; pobrTB.Text = ""; fundTB.Text = "";                    
            }
            else
            {
                Test.Text = "Ha ocurrido un problema, favor intentar más tarde.";
                Test.ForeColor = System.Drawing.Color.Gray;
                guardarNecesBTN.Visible = false;
                cerrarModBTN.Visible = true;
                intDDL.SelectedIndex = 0;
                loadMeses(); loadAnos();
                empTB.Text = ""; pobTB.Text = ""; pobrTB.Text = ""; fundTB.Text = "";
            }
        }
        else
        {
            Test.Text =  Test.Text + "Faltan campos por completar.";
            Test.ForeColor = System.Drawing.Color.Red;
        }
    }

    protected void closePopUp(object sender, EventArgs e)
    //Function used to call the JavaScript function that closes the modal popup.
    {
        ScriptManager.RegisterStartupScript(this, GetType(), "closeMod", "closeMod();", true);
    }
}

最终编辑： 我已经解决了这个问题。这是因为在 IIS 管理器下的应用程序配置中启用视图状态属性设置为 false。将其更改为 true，现在它的工作方式与本地相同。

【问题讨论】：

请发布一些代码 - 向我们展示您的前端代码和 .cs 文件代码

标签： c# asp.net combobox server-side

【解决方案1】：

首先，在loadMeses() 函数中添加mesDDL 下拉列表的清除。其次，你的 sql 查询在哪里？我没找到。

【讨论】：

您的回答应该是评论。 intDDL 是唯一从数据库表加载的 ddl，它在 intList = boNeces.loadIntendencias(Convert.ToInt32(Session["reg_usu"].ToString()), Convert.ToInt32(Session["niv_usu"].ToString())); 行中这样做，来自业务层的“loadIntendencias()”方法从具有查询的数据层调用另一个方法。您是否建议我也发布该代码？
@glenLambert 是的，我想是的