Question

我在按钮点击事件上创建一些动态文本框，在另一个按钮上点击我想使用findcontrol方法获取该文本框的数据

 public void addDepartmentBtn_Click(object sender, EventArgs e)
    {

        int count = Convert.ToInt32(countTxtBx.Text);
        lblErrorMsg.Text = "";
        if (Convert.ToInt32(countTxtBx.Text) <= 5)
        {

            for (int i = 0; i < count; i++)
            {
                Label lb = new Label();
                TextBox tb = new TextBox();

                tb.ID = "Textbox_" + i;
                lb.ID = "Label_" + i;
                lb.Text = "Enter Departnment Name: " + Convert.ToInt32(i + 1);
                pnlMain.Controls.Add(new LiteralControl("<br>"));
                pnlMain.Controls.Add(lb);
                pnlMain.Controls.Add(new LiteralControl("&nbsp&nbsp"));
                pnlMain.Controls.Add(tb);
                pnlMain.Controls.Add(new LiteralControl("<br><br>"));
                lblErrorMsg.Text = Convert.ToInt32(i + 1) + "  Departments Created Successfully";
                //string str = string.Empty;
                //TextBox myTB = (TextBox)pnlMain.FindControl("Textbox_" + i);
                //str = myTB.Text;
                //Response.Write(str);

            }

        }
        else
        {
            lblErrorMsg.Text = "You cannot create more than 5 Departments at once:";
        }
    }

在按钮2上单击：

   protected void Button2_Click(object sender, EventArgs e)
        {
            string alltextdata = null;
            for (int i = 0; i < 5; i++)
            {
                Control controltxt = FindControl("Textbox_"+i);
                if (controltxt != null)
                {
                    TextBox txttemp = (TextBox)controltxt;
                    alltextdata = txttemp.Text;

                }
            }

        }

但我的find控制方法总是显示null我检查我的html页面查看源，它显示我的每个东西都正确我的文本框名称和id是“Textbox_0”，Textbox_1等

我在做错了吗？请帮忙

Answer 1

当您动态添加控件时，它不会在回发后添加到控件树中（button2回发）。在单击addDepartmentBtn之后，您需要在任何回发中的Page_Load事件中再次添加它。

在ViewState中单击保存该按钮并在Page_Load：

中进行检查

public void addDepartmentBtn_Click(object sender, EventArgs e)
    {
        ViewState["addDepartmentBtn_Clicked"] = true;
        AddTextBoxes();
    }

protected void Page_Load(object sender, EventArgs e)
{
    if (Convert.ToBoolean(ViewState["addDepartmentBtn_Clicked"]) == true)
        AddTextBoxes();
}

public void AddTextBoxes()
{
int count = Convert.ToInt32(countTxtBx.Text);
        lblErrorMsg.Text = "";
        if (Convert.ToInt32(countTxtBx.Text) <= 5)
        {

            for (int i = 0; i < count; i++)
            {
                Label lb = new Label();
                TextBox tb = new TextBox();

                tb.ID = "Textbox_" + i;
                lb.ID = "Label_" + i;
                lb.Text = "Enter Departnment Name: " + Convert.ToInt32(i + 1);
                pnlMain.Controls.Add(new LiteralControl("<br>"));
                pnlMain.Controls.Add(lb);
                pnlMain.Controls.Add(new LiteralControl("&nbsp&nbsp"));
                pnlMain.Controls.Add(tb);
                pnlMain.Controls.Add(new LiteralControl("<br><br>"));
                lblErrorMsg.Text = Convert.ToInt32(i + 1) + "  Departments Created Successfully";
                //string str = string.Empty;
                //TextBox myTB = (TextBox)pnlMain.FindControl("Textbox_" + i);
                //str = myTB.Text;
                //Response.Write(str);

            }

        }
        else
        {
            lblErrorMsg.Text = "You cannot create more than 5 Departments at once:";
        }
}

Answer 2

在调用findcontrol方法之前，必须再次加载该contro，因为它是在每次回发时动态创建的。这些不像我们在Page_Init下创建的静态控件。动态控件在Page_Load事件下创建。

asp.net findcontrol方法返回null

2 个答案: