如何获取动态创建的文本框的文本值

Question

I want to get the value of my textbox that I created dynamically when I click a button

I need to do this cause the value of my textbox is used for retrieve data from database

how could I achieved this thing??

the flow is Button click - creating textbox - filling textbox with value - Button Click - Get Text of textbox

here is my code to make the textbox

Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    For i As Integer = 0 To 4
        textbox = New TextBox With {.ID = "TextBox" & i}
        plchld.Controls.Add(textbox)
    Next
End Sub

I have tried something like this but the code didn't work

Protected Sub OkButton_Click(sender As Object, e As EventArgs) Handles OkButton.Click
    Dim a(5) As String
    For i As Integer = 0 To 4
        a(i) = CType(plchld.FindControl("Textbox" & i), TextBox).Text
    Next
End Sub

thanks in advance for any help

edit for the answer

I've found the way to solve this. I use request.form to get the value of my textbox.

Thanks for anyone that participating

Regards,

Julian

Answer 1

This is how I have done in my asp.net application.

Creating dynamic control

TextBox txtDate = new TextBox();
txtDate.EnableViewState = true;
txtDate.ID = "PreixValue" + 1;
txtDate.Text = "07 Feb 2014"
pnl.controls.add(txtdate); 

To retrieve the value from that textbox

DateTime datefrom = DateTime.Now ;

                for (int cnt = 0; cnt < Request.Form.Count; cnt++)
                {
                    if (Request.Form.AllKeys[cnt].Contains("Prefixvalue"))
                    {
                        int ParamStartPoint = Request.Form.AllKeys[cnt].IndexOf("Prefix") + 4;
                        int ParamNameLength = Request.Form.AllKeys[cnt].Length - ParamStartPoint;

                        string[] ControlName = Request.Form.AllKeys[cnt].Substring(ParamStartPoint, ParamNameLength).Split('$');

                                if (ControlName[0] == "Date From")
                                {

                    datefrom = DateTime.Parse(Request.Form[cnt]); 
                    //datefrom has value now
                                }
    }
}

This is how I have done in my web application, but there may be other ways achieve this.

basically when you create Dynamic control in webform this will be available through Request.Form.

hope this helps you.

Answer 2

Protected Sub OkButton_Click(sender As Object, e As EventArgs) Handles OkButton.Click
Dim a(5) As String
For i As Integer = 0 To 4
  Dim anotherObj As TextBox = Me.Controls.Item("Textbox" & i)  
  a(i) =anotherObj.Text
Next 

Answer 3

The issue is that dynamic controls are lost on a postback so when the OkButton click event is handled, there is nothing inside your plchld control. You must recreate your controls with the same ID on postback if you want to retrieve the text in the textboxes.

Using your code, all you need to do is on postback determine if the textboxes were created and if so, recreate them.

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
    ' Determine if the text boxes were created and if so, recreate them.
    If CBool(ViewState("TextBoxesCreated")) Then
        CreateTextBoxes()
    End If
End Sub

Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click
    CreateTextBoxes()
    ViewState("TextBoxesCreated") = True
End Sub

Private Sub CreateTextBoxes()
    For i As Integer = 0 To 4
        plchld.Controls.Add(New TextBox With {.ID = "TextBox" & i})
    Next
End Sub

Protected Sub OkButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles OkButton.Click
    Dim a(4) As String
    For i As Integer = 0 To 4
        a(i) = CType(plchld.FindControl("Textbox" & i), TextBox).Text
    Next
End Sub

I don't know the full extent of what you are doing but I would suggest not creating them dynamically if you don't need to. Just show or hide the textboxes instead.

Reference: http://www.codeproject.com/Articles/3684/Retaining-State-for-Dynamically-Created-Controls-i