查找动态创建的控件时出错

时间：2013-07-31 06:26:01

标签： c# asp.net html5 file-upload dynamic-controls

我使用Fileupload控件上传图片，当我点击上传按钮加载文件后，文件将保存在服务器的文件夹中，但在保存到数据库之前我需要添加图像描述和图像..但是我不知道我收到了一些错误。我能够将文件保存在文件夹中，但是当我将其保存到数据库中时，只能找到一个动态添加的控件，然后它会将对象引用设置为未设置为对象即使有多个控制在那个特定的div。在进入代码之前，我将告诉我在上传文件后添加了哪些控件..我为我上传的每个图像文件添加了一个图像控件和文本框..当我只上传一个文件时，它将简单地进入foreach第一次之后再次循环..我的代码可能会解释得更多。

所以这是我的.aspx代码：

<form id="ContentPlaceHolder1" runat="server">

    <div class="transbox" id="mainbk" runat="server" style="position:absolute; top:0px; left:0px; width: 100%; height: 100%;" >
      <asp:FileUpload runat="server" ID="UploadImages" style="background-color:white; position:absolute; font-family:'Palatino Linotype'; font-size:medium; top: 4px; left: 350px; right: 251px;" Width="500px" AllowMultiple="true"/>

        <asp:Button runat="server" ID="uploadedFile" style="position:absolute;  font-family:'Palatino Linotype'; font-size:medium; top: 4px; left: 870px; width: 112px; height: 29px;" Text="Upload" OnClick="uploadFile_Click" />
        <asp:Panel ID="updtpanel" runat="server" CssClass="transbox" style="width:100%;height:100%;left:0px;top:0px;position:absolute" Visible="false">
             <asp:Button ID="btnsave" runat="server" UseSubmitBehavior="true" Text="Save" OnClick="btnsave_Click" Font-Bold="true" BackColor="Yellow"></asp:Button>

        </asp:Panel>
     </div>


    </form>

这是我的后端代码。

SqlCommand com = new SqlCommand();
SqlConnection con = new SqlConnection();
SqlDataReader reader;
int id = 0;
StringBuilder sb = new StringBuilder();
string filepath = "";
string newpath = "";
int tid = 0;
int count = 0;
int cnt1 = 0;
string textid = "";
Panel dload;
Image img;
TextBox ta;
protected void Page_Load(object sender, EventArgs e)
{

    con.ConnectionString = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
    con.Open();
    com = new SqlCommand("select max(slid) from slider", con);
    reader = com.ExecuteReader();
    if (reader.HasRows)
    {
        while (reader.Read())
        {
            id = Convert.ToInt32(reader.GetInt32(0));
        }
    }
    con.Close();
    com.Dispose();
    HtmlGenericControl dh = new HtmlGenericControl("div");
    dh.Attributes.Add("class", "head");
    dh.InnerText = "Write Description";
    updtpanel.Controls.Add(dh);
    foreach (HttpPostedFile upld in UploadImages.PostedFiles)
    {
        createImgPanel();
    }
}



protected void uploadFile_Click(object sender, EventArgs e)
{
    if (UploadImages.HasFiles)
    {
       string fileExt = Path.GetExtension(UploadImages.FileName).ToLower();
       if (fileExt == ".jpeg" || fileExt == ".png" || fileExt == ".jpg" || fileExt == ".bmp")
       {
           foreach (HttpPostedFile uploadedFile in UploadImages.PostedFiles)
           {
               count += 1;
               filepath = Server.MapPath("~/Images/Gallery/" + uploadedFile.FileName);
               uploadedFile.SaveAs(filepath);
               newpath = "../Images/Gallery/" + uploadedFile.FileName;
               try
               {
                   Image nimg = dload.FindControl("img" + count) as Image;
                   nimg.ImageUrl = newpath.ToString();
               }

               catch (Exception ex)
               {
                   Response.Write(ex.Message);
               }

           }
       }
       else
       {
           Page.ClientScript.RegisterStartupScript(GetType(), "msgbox", "alert('Please Select only Image Files!!');", true);
       }

    }
    else
    {
        Page.ClientScript.RegisterStartupScript(GetType(), "msgbox", "alert('Please Select a File First!!');", true);        
    }
}

public void createImgPanel()
{
    tid = tid + 1;
    textid = "txt" + tid;
    ta = new TextBox();
    img = new Image();
    ta.TextMode = TextBoxMode.MultiLine;
    dload = new Panel();
    updtpanel.Visible = true;
    dload.Attributes.Add("class", "dataload");
    //dload.Attributes.Add("runat", "server");
    dload.ID = "ind" + tid;
    img.CssClass = "loadimg";

    img.ID = "img" + tid;
    //img.Attributes.Add("runat", "server");
    ta.Attributes.Add("class", "txtdes");
    ta.ID = textid;
    //ta.Attributes.Add("runat", "server");
    dload.Controls.Add(img);
    dload.Controls.Add(ta);
    updtpanel.Controls.Add(dload);
}

protected void btnsave_Click(object sender, EventArgs e)
{
    if (Page.IsPostBack)
    {

            Panel pv = (this.Form.FindControl("mainbk").FindControl("updtpanel")) as Panel;

            foreach (Control cd in pv.Controls)
            {
                cnt1 = cnt1 + 1;
                TextBox txt = cd.FindControl("ind" + cnt1).FindControl("txt" + cnt1) as TextBox;****This is where I am getting the above said error****
                Image img = cd.FindControl("ind" + cnt1).FindControl("img" + cnt1) as Image;

                    string str = "";
                    str = txt.Text;
                    string iurl = "";
                    iurl = img.ImageUrl;

                    id += 1;

                    string Insert = "Insert into slider (slid,slurl,slalt) values (@id,@IMAGE_PATH,@alter)";
                    SqlCommand cmd = new SqlCommand(Insert, con);
                    cmd.Parameters.AddWithValue("@IMAGE_PATH", iurl);
                    cmd.Parameters.AddWithValue("@id", id);
                    cmd.Parameters.AddWithValue("@alter", str);
                    try
                    {
                        con.Open();
                        cmd.ExecuteNonQuery();
                        con.Close();

                    }
                    catch (Exception e1)
                    {
                        Response.Write(e1.Message);
                    }
                }





        updtpanel.Visible = false;
    }
}

* 我在上面代码的最后部分出现错误，即保存按钮点击事件。对于Textbox Find控件，我收到错误。第一张图像将成功保存，但对于其他图像，即使它们出现在设计中，也无法找到控件。 *

我只是想知道我是否在保存点击事件中犯了任何错误，或者整个编码本身是否有任何错误

修改

因此，这是在运行时呈现控件之后的HTML源代码：

    <div id="mainbk" class="transbox" style="position:absolute; top:0px; left:0px; width: 100%; height: 100%;">
          <input type="file" multiple="multiple" name="UploadImages" id="UploadImages" style="width:500px;background-color:white; position:absolute; font-family:'Palatino Linotype'; font-size:medium; top: 4px; left: 350px; right: 251px;">

            <input type="submit" name="uploadedFile" value="Upload" id="uploadedFile" style="position:absolute;  font-family:'Palatino Linotype'; font-size:medium; top: 4px; left: 870px; width: 112px; height: 29px;">
            <div id="updtpanel" class="transbox" style="width:100%;height:100%;left:0px;top:0px;position:absolute">

                 <input type="submit" name="btnsave" value="Save" id="btnsave" style="background-color:Yellow;font-weight:bold;">

            <div class="head">Write Description</div><div id="ind1" class="dataload">
            <img id="img1" class="loadimg" runat="server" src="../Images/Gallery/God%201.jpg">
<textarea name="txt1" rows="2" cols="20" id="txt1" class="txtdes"></textarea>
        </div><div id="ind2" class="dataload">
            <img id="img2" class="loadimg" runat="server" src="../Images/Gallery/God%202.jpg">
<textarea name="txt2" rows="2" cols="20" id="txt2" class="txtdes"></textarea>
        </div><div id="ind3" class="dataload">
            <img id="img3" class="loadimg" runat="server" src="../Images/Gallery/God%203.jpg">
<textarea name="txt3" rows="2" cols="20" id="txt3" class="txtdes"></textarea>
        </div>
    </div>
         </div>

被修改

K我刚刚深入了解我得到的例外......它的说法......

'（（System.Web.UI.HtmlControls.HtmlContainerControl）（dv））。InnerHtml'引发了'System.Web.HttpException'类型的异常

这实际意味着什么..它还说控制不是文字的..这是什么意思..为什么它无法找到我附加的控件.. 帮帮我请..

2 个答案:

答案 0 :(得分：0)

在PreRender事件中添加控件，至少从PageLoad访问它们。

答案 1 :(得分：0)

在向浏览器呈现后，您是否还可以包含HTML源代码？ 如果cd.FindControl("ind" + cnt1)在第一种情况下返回null，该怎么办？

cd.FindControl("ind" + cnt1).FindControl("txt" + cnt1) as TextBox
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