Question

我有以下代码：

foreach (ListItem item in check.Items)
            {
                if (item.Selected)
                {
                    TableRow row = new TableRow();
                    row.Style.Add("color", "white");
                    TableCell cell = new TableCell();
                    cell.Style.Add("background-color", "blue");
                    Label lbl = new Label();
                    lbl.Text = item.Text;
                    cell.Controls.Add(lbl);

                    row.Cells.Add(cell);
                    TableCell cell1 = new TableCell();
                    cell1.Style.Add("background-color", "green");
                    DropDownList drop = new DropDownList();

                    drop.Style.Add("align", "right");
                    drop.Items.Add(" ");
                    drop.Items.Add("1");
                    drop.Items.Add("2");
                    drop.DataValueField = "0";
                    drop.DataValueField = "1";
                    drop.DataValueField = "2";

                    cell1.Controls.Add(drop);
                    row.Cells.Add(cell1);
                    this.TblCheck.Rows.Add(row);

                    drop.SelectedIndexChanged += new EventHandler(drop_SelectedIndexChanged);
                    drop.AutoPostBack = true;
                }
            }
        }


                    private void drop_SelectedIndexChanged(object sender,EventArgs e)
                    {
                        if (drop.SelectedValue == "1")
                        {

                            TableRow row = new TableRow();
                            TableCell cell = new TableCell();
                            cell.Style.Add("background-color", "blue");
                            Label lbl = new Label();
                            lbl.Text = "H1";
                            cell.Controls.Add(lbl);
                            row.Cells.Add(cell);
                            this.tabel1.Rows.Add(row);
                        }

                        if (drop.SelectedValue == "2")
                        {
                            TableRow row = new TableRow();
                            TableCell cell = new TableCell();
                            cell.Style.Add("background-color", "blue");
                            Label lbl = new Label();
                            lbl.Text = "H1";
                            cell.Controls.Add(lbl);
                            row.Cells.Add(cell);
                            TableRow row1 = new TableRow();
                            TableCell cell1 = new TableCell();
                            cell1.Style.Add("background-color", "blue");
                            Label lbl1 = new Label();
                            lbl1.Text = "H2";
                            cell1.Controls.Add(lbl1);
                            row1.Cells.Add(cell1);
                            this.tabel1.Rows.Add(row);
                            this.tabel1.Rows.Add(row1);
                        }


                    }

我有一个下拉列表，当我为每个选项选择一个选项时，会创建一个包含所选值的行，另一个列包含一个下拉列表。我希望为创建的动态下拉列表添加一个selectedindexchanged.I请问如何在我的selectedindexchanged中引用动态创建的下拉列表，其名称为“drop”。我试图将其公开但我的表格创建得不好。这是一个使用c＃的as.net Web应用程序。

Answer 1

在SelectedIndexChanged事件中，您可以访问触发事件的对象。在您的情况下，它将是您将事件关联到的动态创建的控件。您可以在事件中键入cast作为DropDownList，如下所示：

protected void drop_SelectedIndexChanged(object sender, EventArgs e)
{
    var drop = (DropDownList)sender;
    if (drop.SelectedValue == "1")
    {
      ...
    }
}

将动态创建的下拉列表公开给其他类

1 个答案: