C# 在行数据绑定事件上找不到隐藏的输入控件

这是我的aspx文件内容

这是.cs端

private LMSDataAccess.LookupsDataContext LkpDC = new LMSDataAccess.LookupsDataContext(ConfigFile.DBConnStr);
private System.Collections.Generic.List<LMSDataAccess.GeneralSetting> GeneralSettingList = null;


protected void Page_Load(object sender, EventArgs e)
{
    base.ModuleID = 27;

    if (!IsPostBack)
    {
        if (Request["AID"] != null)
            hdnAID.Value = Request["AID"];

        BindData();
    }
}

private void BindData()
{
    GeneralSettingList = LkpDC.GeneralSettingsGetAll(Common.NVLInt(hdnAID.Value),null).ToList();
    GridView1.DataSource = GeneralSettingList;
    GridView1.DataBind();
}

protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
{
    GridView1.EditIndex = -1;
    BindData();
}
protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
{
    GridView1.EditIndex = e.NewEditIndex;
    BindData();
}
protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
    TextBox txtUpdateGeneralSettingName = (TextBox)GridView1.Rows[e.RowIndex].FindControl("txtUpdateGeneralSettingName");
    TextBox txtUpdateGeneralSettingValue = (TextBox)GridView1.Rows[e.RowIndex].FindControl("txtUpdateGeneralSettingValue");
    var hdnCompany = (HiddenField)GridView1.Rows[e.RowIndex].FindControl("hdnCompanyId") as HiddenField;

    string KeyValue = GridView1.DataKeys[e.RowIndex].Value.ToString();

    LkpDC.GeneralSettingsUpdate(Convert.ToInt32(KeyValue),
        txtUpdateGeneralSettingName.Text,
        txtUpdateGeneralSettingValue.Text, 
        Convert.ToInt32(hdnCompany.Value));

    GridView1.EditIndex = -1;
    BindData();
    ResultCode = 0;
}

protected List<LMSDataAccess.Company> GetAllCompanies()
{
    System.Collections.Generic.List<LMSDataAccess.Company> CompanyList = null;
    LMSDataAccess.OrganizationDataContext OrgDC = new LMSDataAccess.OrganizationDataContext(ConfigFile.DBConnStr);

    CompanyList = OrgDC.CompaniesGetAll(null).ToList();
    return CompanyList;
}
protected void drpCompanyList_SelectedIndexChanged(object sender, EventArgs e)
{

    DropDownList ddl = (DropDownList)sender;        
    GridViewRow row = (GridViewRow)ddl.Parent.Parent;
    var hdnCompany = row.FindControl("hdnCompanyId") as HiddenField;
    hdnCompany.Value = ddl.SelectedValue;        
}
protected void GridView1_RowDataBound(object sender,GridViewRowEventArgs e) 
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        var ddl = e.Row.FindControl("drpCompanyList") as DropDownList;
        //here is the problem.
        var hdn = e.Row.FindControl("hdnCompanyId") as HiddenField;

        if (ddl != null)
        {
            ddl.DataSource = GetAllCompanies();
            ddl.DataValueField = "CompanyID";
            ddl.DataTextField = "CompanyName";
            ddl.DataBind();

        }
    }
}

private LMSDataAccess.LookupsDataContext LkpDC=new LMSDataAccess.LookupsDataContext（ConfigFile.DBConnStr）；
private System.Collections.Generic.List GeneralSettingList=null；
受保护的无效页面加载（对象发送方、事件参数e）
{
base.ModuleID=27；
如果（！IsPostBack）
{
如果（请求[“援助”]！=null）
hdnAID.Value=Request[“AID”]；
BindData（）；
}
}
私有void BindData（）
{
GeneralSettingList=LkpDC.GeneralSettingsGetAll（Common.NVLInt（hdnAID.Value），null.ToList（）；
GridView1.DataSource=通用设置列表；
GridView1.DataBind（）；
}
受保护的无效GridView1\u行取消编辑（对象发件人，GridViewCancelEditEventArgs e）
{
GridView1.EditIndex=-1；
BindData（）；
}
受保护的无效GridView1_行编辑（对象发送方，GridViewEditEventArgs e）
{
GridView1.EditIndex=e.NewEditIndex；
BindData（）；
}
受保护的无效GridView1_行更新（对象发送方，GridViewUpdateEventArgs e）
{
TextBox txtUpdateGeneralSettingName=（TextBox）GridView1.Rows[e.RowIndex].FindControl（“txtUpdateGeneralSettingName”）；
TextBox txtUpdateGeneralSettingValue=（TextBox）GridView1.Rows[e.RowIndex].FindControl（“txtUpdateGeneralSettingValue”）；
var hdnCompany=（HiddenField）GridView1.Rows[e.RowIndex].FindControl（“hdnCompanyId”）作为HiddenField；
string KeyValue=GridView1.DataKeys[e.RowIndex].Value.ToString（）；
LkpDC.GeneralSettingsUpdate（转换为32（键值），
txtUpdateGeneralSettingName.Text，
txtUpdateGeneralSettingValue.Text，
转换为32（hdnCompany.Value））；
GridView1.EditIndex=-1；
BindData（）；
结果代码=0；
}
受保护列表GetAllCompanys（）
{
System.Collections.Generic.List CompanyList=null；
LMSDataAccess.OrganizationDataContext OrgDC=新的LMSDataAccess.OrganizationDataContext（ConfigFile.DBConnStr）；
CompanyList=OrgDC.companyGetAll（null.ToList（）；
返回公司列表；
}
受保护的无效drpCompanyList\u SelectedIndexChanged（对象发送方，事件参数e）
{
DropDownList ddl=（DropDownList）发送方；
GridViewRow=（GridViewRow）ddl.Parent.Parent；
var hdnCompany=row.FindControl（“hdnCompanyId”）作为HiddenField；
hdnCompany.Value=ddl.SelectedValue；
}
受保护的void GridView1_RowDataBound（对象发送方，GridViewRowEventArgs e）
{
如果（e.Row.RowType==DataControlRowType.DataRow）
{
var ddl=e.Row.FindControl（“drpCompanyList”）作为DropDownList；
//问题就在这里。
var hdn=e.Row.FindControl（“hdnCompanyId”）作为HiddenField；
如果（ddl！=null）
{
ddl.DataSource=getAllCompanys（）；
ddl.DataValueField=“CompanyID”；
ddl.DataTextField=“CompanyName”；
ddl.DataBind（）；
}
}
}

我最喜欢的问题是，当GridView1\u RowDataBound和drpCompanyList\u选择DexChangedFeed时，无法获取hdnCompanyId元素。我总是得到null。（如注释行所示）

我在GridView1_RowDataBound事件方法下尝试过，比如

e.Row.FindControl（“hdnCompanyId”）

但它没有起作用。 我的最终目标是设置并获取此元素以控制dropdownlist中的选定项

我认为代码写得很好，但我想我缺少了一些关于用户控件元素层次结构的东西。

---

你能帮我解释一下我遗漏了什么吗？

我发现问题在于选择了错误的输入类型。它必须是

HtmlInputHidden

，而不是

HiddenField

。我希望有人能从这个问题中获得有用的信息

private LMSDataAccess.LookupsDataContext LkpDC = new LMSDataAccess.LookupsDataContext(ConfigFile.DBConnStr);
private System.Collections.Generic.List<LMSDataAccess.GeneralSetting> GeneralSettingList = null;


protected void Page_Load(object sender, EventArgs e)
{
    base.ModuleID = 27;

    if (!IsPostBack)
    {
        if (Request["AID"] != null)
            hdnAID.Value = Request["AID"];

        BindData();
    }
}

private void BindData()
{
    GeneralSettingList = LkpDC.GeneralSettingsGetAll(Common.NVLInt(hdnAID.Value),null).ToList();
    GridView1.DataSource = GeneralSettingList;
    GridView1.DataBind();
}

protected void GridView1_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e)
{
    GridView1.EditIndex = -1;
    BindData();
}
protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
{
    GridView1.EditIndex = e.NewEditIndex;
    BindData();
}
protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
    TextBox txtUpdateGeneralSettingName = (TextBox)GridView1.Rows[e.RowIndex].FindControl("txtUpdateGeneralSettingName");
    TextBox txtUpdateGeneralSettingValue = (TextBox)GridView1.Rows[e.RowIndex].FindControl("txtUpdateGeneralSettingValue");
    var hdnCompany = (HiddenField)GridView1.Rows[e.RowIndex].FindControl("hdnCompanyId") as HiddenField;

    string KeyValue = GridView1.DataKeys[e.RowIndex].Value.ToString();

    LkpDC.GeneralSettingsUpdate(Convert.ToInt32(KeyValue),
        txtUpdateGeneralSettingName.Text,
        txtUpdateGeneralSettingValue.Text, 
        Convert.ToInt32(hdnCompany.Value));

    GridView1.EditIndex = -1;
    BindData();
    ResultCode = 0;
}

protected List<LMSDataAccess.Company> GetAllCompanies()
{
    System.Collections.Generic.List<LMSDataAccess.Company> CompanyList = null;
    LMSDataAccess.OrganizationDataContext OrgDC = new LMSDataAccess.OrganizationDataContext(ConfigFile.DBConnStr);

    CompanyList = OrgDC.CompaniesGetAll(null).ToList();
    return CompanyList;
}
protected void drpCompanyList_SelectedIndexChanged(object sender, EventArgs e)
{

    DropDownList ddl = (DropDownList)sender;        
    GridViewRow row = (GridViewRow)ddl.Parent.Parent;
    var hdnCompany = row.FindControl("hdnCompanyId") as HiddenField;
    hdnCompany.Value = ddl.SelectedValue;        
}
protected void GridView1_RowDataBound(object sender,GridViewRowEventArgs e) 
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        var ddl = e.Row.FindControl("drpCompanyList") as DropDownList;
        //here is the problem.
        var hdn = e.Row.FindControl("hdnCompanyId") as HiddenField;

        if (ddl != null)
        {
            ddl.DataSource = GetAllCompanies();
            ddl.DataValueField = "CompanyID";
            ddl.DataTextField = "CompanyName";
            ddl.DataBind();

        }
    }
}