Question

我的页面上有很少的文本框，这些文本框是在下拉列表中的文本更改时动态加载的。用户在这些文本框中输入值并单击addnewitem按钮。在后面的代码中，我想捕获在这些文本框中输入的值。但我得到的值是空的。

On Pageload mthd没有任何内容引用createdynamiccontrols方法。然后我

    protected override void CreateChildControls()
    {
        base.CreateChildControls();
        CreateDynamicControls();

    }

    protected override void OnLoad(EventArgs e)
    {
        base.OnLoad(e);
    }

    protected override object SaveViewState()
    {
        return new Pair(base.SaveViewState(), null);
    }

    protected override void LoadViewState(object savedState)
    {
        base.LoadViewState(((Pair)savedState).First);

        EnsureChildControls();
    }

 public void CreateDynamicControls()
    { 
        Student= ddlStudentschool.SelectedItem.Text.ToString();
        studentcollege= ddlstudentcollege.SelectedValue.ToString();  
        int rowPos = 0;


        DynPanel.BorderStyle = BorderStyle.Solid;

根据所选的studentchool和studentcollege，以下文本框和＆amp;将创建字段名

        Label Mynewlabel = new Label();
        Mynewlabel.ID = "lbl" + FldLabel;
        Mynewlabel.Text = FldLabel;
        Mynewlabel.Visible = true;
        Mynewlabel.Font.Bold = true;
        DynPanel.Controls.Add(new LiteralControl("<td bgcolor=#333>"));
        DynPanel.Controls.Add(Mynewlabel);
        DynPanel.Controls.Add(new LiteralControl("</td>"));


        if (ControlType == "TextBox")
        {
            int textBoxLength;
            TextBox MynewTextBox = new TextBox();
            MynewTextBox.ID = "txt" + Fldname;

            MynewTextBox.Width = 100;
            MynewTextBox.EnableViewState = true;
            MynewTextBox.Enabled = true;
         did not paste the whole code
       }
   protected void DropDownList1_SelectedIndexChanged1(object sender, EventArgs e)
    {
        CreateDynamicControls();
    }

  protected void btnAddItem_Click(object sender, EventArgs e)
    {
        CreateDynamicControls();

        if (DynPanel.Controls != null)
        {
            foreach (Control ctrl in DynPanel.Controls)
            {
                if (ctrl is TextBox)
                {
                    TextBox _txt = DynPanel.FindControl(ctrl.ID) as TextBox; 
                    int count = DynPanel.Controls.Count;
                    // txtresult.ID = ctrl.ID;
                    txtresult.Text = ((TextBox)ctrl).Text;
                    TextBox txtPath = (TextBox)ctrl.FindControl("");
                    string result = txtresult.Text;
                }

首先，当第二次调用createchildcontrols方法时，我没有将对象引用设置为对象的实例，并且如果我在additem click事件中没有createdynamiccontrols方法，则控件不再是tehre ...

Answer 1

这可能与你如何加载控件有关。在回发后，您需要将动态控件重新加载到最初加载的相同位置。否则视图状态将不匹配，并且控制状态无法加载到控制树中。如果这不起作用，请发布更多代码！

Answer 2

您需要re-create dynamic control on each postback，查看我之前对类似问题的回答here

无法获取用户在按钮单击事件上输入的值，将在动态加载的文本框中输入值

2 个答案: