通過動態創建文本框獲取文本值

Question

給定多個動態創建的文本框，我想讓用戶填寫文本。 我使用了面板並進行了創作。 找不到文本框的控件。

ASPX

<div>
  <asp:Panel ID="Panel1" runat="server"></asp:Panel>
</div>
<div>
  <asp:Button ID="Button1" runat="server" Text="Adauga autor" OnClick="Button1_Click" />
</div>

創建文本框

protected void Button1_Click(object sender, EventArgs e)
{
    int rowCount = Convert.ToInt32(Session["clicks"]);
    rowCount++;
    Session["clicks"] = rowCount;

    for (int i = 1; i <= rowCount; i++)
    {
        TextBox TxtBoxA = new TextBox();
        Label lblA = new Label();

        TxtBoxA.ID = "TextBoxA" + i.ToString();
        lblA.ID = "LabelA" + i.ToString();
        lblA.Text = "Label" + i.ToString() + ": ";

        Panel1.Controls.Add(lblA);
        Panel1.Controls.Add(TxtBoxA);
        Panel1.Controls.Add(new LiteralControl("<br />"));
    }
}

取得文字

int rowCount = Convert.ToInt32(Session["clicks"]);
for (int i = 1; i <= rowCount; i++)
{
    string item = "TextBoxA" + i.ToString();
    Control foundControl = FindControl(item, Page.Controls);
    TextBox TB = (TextBox)foundControl;
    string txt = TB.Text;
}

+

public static Control FindControl(string controlId, ControlCollection controls)
{
    foreach (Control control in controls)
    {
        if (control.ID == controlId)
            return control;

        if (control.HasControls())
        {
            Control nestedControl = FindControl(controlId, control.Controls);

            if (nestedControl != null)
                return nestedControl;
        }
    }
    return null;
}

文本框控件為空。 我究竟做錯了什么？

Answer 1

您必須最遲在Page_Load中重新創建所有控件。 Button1_Click為時已晚。 因此，在Page_Init / Page_Load重新創建Session["clicks"]並在Button-Click -handler中創建單個新控件。

一些代碼：

protected void Page_Init(Object sender, EventArgs e)
{
    RecreateControls();
}

 private void RecreateControls()
 {
     int rowCount = Convert.ToInt32(Session["clicks"]);
     CreateControls(rowCount);
 }

 private void AddControl()
 {
     int rowCount = Convert.ToInt32(Session["clicks"]);
     CreateControls(1);
     Session["clicks"] = rowCount++;
 }

 private void CreateControls(int count)
 {
     for (int i = 1; i <= count; i++)
     {
         TextBox TxtBoxA = new TextBox();
         Label lblA = new Label();

         TxtBoxA.ID = "TextBoxA" + i.ToString();
         lblA.ID = "LabelA" + i.ToString();
         lblA.Text = "Label" + i.ToString() + ": ";

         Panel1.Controls.Add(lblA);
         Panel1.Controls.Add(TxtBoxA);
         Panel1.Controls.Add(new LiteralControl("<br />"));
     }
 }

 protected void Button1_Click(object sender, EventArgs e)
 {
     AddControl();
 }