如何使用静态 ClientIDMode 访问动态添加到页面的控件

Question

我有一个简单的页面，有 1 个 PlaceHolder 和 2 个按钮（“添加行”，“获取值”），没有别的。当我点击添加行按钮时，我创建了一个动态表并在它的单元格中放置了一些控件设置 ClientIDMoode=static:

private void CreateTableWithSession(bool FirstLoad)
{
    Table tbl;
    int Row;
    if (Session["tbl"]==null)
    {
        tbl = new Table();
    }
    else
    {
        tbl = (Table)Session["tbl"];
    }
    if (FirstLoad == true)
    {
        tbl.Rows.Clear();
    }
    //////////////////////////////////////////////////
    if (Session["Row"] == null)
    {
        Row = 0;
    }
    else
    {
        Row = int.Parse(Session["Row"].ToString());
    }
    if (FirstLoad == true)
    {
        tbl.Rows.Clear();
    }
    //////////////////////////////////////////////////

    TableRow tr1 = new TableRow();
    TableCell tc = new TableCell();

    TextBox txtBoxUserName = new TextBox();
    txtBoxUserName.ClientIDMode = System.Web.UI.ClientIDMode.Static;
    txtBoxUserName.Text = "0";
    Col++;
    txtBoxUserName.ID = "RowNo" + Row.ToString() + "ColumnNo" + Col.ToString();
    tc.Controls.Add(txtBoxUserName);
    tc.Width = 200;
    tc.VerticalAlign = VerticalAlign.Middle;
    tc.HorizontalAlign = HorizontalAlign.Center;
    tr1.Cells.Add(tc);

    tc = new TableCell();
    TextBox txtBoxPassword = new TextBox();
    txtBoxPassword.ClientIDMode = System.Web.UI.ClientIDMode.Static;
    txtBoxPassword.Text = "0";
    Col++;
    txtBoxPassword.ID = "RowNo" + Row.ToString() + "ColumnNo" + Col.ToString();
    tc.Controls.Add(txtBoxPassword);
    tc.Width = 200;
    tc.VerticalAlign = VerticalAlign.Middle;
    tc.HorizontalAlign = HorizontalAlign.Center;
    tr1.Cells.Add(tc);

    tbl.Rows.Add(tr1);

    Session["tbl"] = tbl;

    PlaceHolder1.Controls.Add(tbl);
}

当用户点击“获取值”按钮时，我希望获得 2 个文本框值（动态添加）。但每次它返回 Null。

TextBox txtBoxUserName = this.FindControl("RowNo1ColumnNo1") as TextBox;

如何解决这个问题并访问文本框值？

谢谢

Answer 1

在您可以访问之前，应该重新创建动态创建的控件，并且我确信当您点击 Get Value 按钮时您没有创建控件。有些东西对你有用...

protected void AddRow_Click(object sender, EventArgs e)
{
   CreateTableWithSession()
   ...................
}

protected void GetValue_Click(object sender, EventArgs e)
{
   CreateTableWithSession()
   TextBox txtBoxUserName = this.FindControl("RowNo1ColumnNo1") as TextBox;
   ........................
}