asp.net - 获取在运行时生成的控制

Question

我正在通过后端在文本更改事件上创建一些文本框，如下所示:

protected void txtHowMany_TextChanged(object sender, EventArgs e)
    {
          int totalSections = Convert.ToInt32(txtHowMany.Text.Trim());

            for (int i = 1; i <= totalSections; i++)
            {
                TextBox tbx = new TextBox();
                tbx.Text = "";
                tbx.ID = "section" + i;
                tbx.Style.Add("width", "90%");
                tdSectionsAdd.Controls.Add(tbx);
            }
            trSectionsName.Visible = true;
    }

自动回发适用于 txtHowMany ，所以当我输入一个数字时，它会生成文本框并将其添加到表分区

现在的问题是，我正在尝试从生成的文本框中获取文本，如下所示:

protected void btnSave_click(object sender, EventArgs e)
    {
      int numbersOfSectionsToSave = 1;
                int sectionsToSave =Convert.ToInt32(txtHowMany.Text.Trim());

                for (int i = 1; i < sectionsToSave; i++)
                {
                    Sections section = new Sections();
                    section.CourseId = result;
                    section.OrganizationId = course.OrganizationId;

                    foreach (Control c in tdSectionsAdd.Controls)
                    {
                        if (c.GetType() == typeof(TextBox))
                        {
                          TextBox  txtBox = (TextBox)c;
                            string id = "section" + i;
                            if (txtBox.ID == id)
                            {
                                section.Name = txtBox.Text.Trim();
                            }
                        }
                    }

                    string name = Request.Form["section1"];
                    section.CreatedBy = "Admin";
                    section.CreationDate = DateTime.Now;
                    section.ModifiedBy = "Admin";
                    section.ModificationDate = DateTime.Now;
                    numbersOfSectionsToSave += section.SaveSection();
    }

但它显示 中的控件计数为 0 tdSectionsAdd , 在我尝试访问它们之前添加了控件，但它仍然没有在 td 中显示任何控件。
请帮忙，我怎样才能得到这些文本框？

谢谢!

Answer 1

您需要在每个回发中添加它们。存储 totalSections ViewState 中的变量，因此您也可以在页面加载时添加它们:

protected void AddTextBoxes()
{
    int totalSections;
    if (int.TryParse(Convert.ToString(ViewState["TotalSections"]), out totalSections)
    {
        for (int i = 1; i <= totalSections; i++)
            {
                TextBox tbx = new TextBox();
                tbx.Text = "";
                tbx.ID = "section" + i;
                tbx.Style.Add("width", "90%");
                tdSectionsAdd.Controls.Add(tbx);
            }
        trSectionsName.Visible = true;
    }
}
protected void txtHowMany_TextChanged(object sender, EventArgs e)
    {
          ViewState["TotalSections"] = Convert.ToInt32(txtHowMany.Text.Trim());

            tdSectionsAdd.Controls.Clear();
            AddTextBoxes();
    }

protected void Page_Load(object sender, EventArgs e)
{
    AddTextBoxes();
}