Question

I have written the user control InputDetails that has a few text boxes and a few radio boxes inside it.

I add it dynamically during Page_Load:

if(!Page.IsPostBack()){
  InputDetails input = (InputDetails)Page.LoadControl("InputDetails.ascx");
  PlaceHolder1.Controls.Add(input);
}

but when I refresh the page, the control is gone, so I’m asking, how do I save the user control in the viewstate that it has been added, so it automatically reloads it next time. Better yet, how do I read the values put in the text boxes of the user control when the page is posted back? I need to be able to add multiple InputDetails on a single page so saving it would be useful.

Answer 1

If you add a control to the page dynamically, you have to recreate it after each postback.
Try to remove the if (Page.IsPostBack()) line and check if it works :).
For each control you create, you should also set the same ID value each time it’s created.
If there are no other issues, the ViewState should then be able to save state of the controls across postbacks.

In order to read the values, you can:

• add some public properties to your user control in order to get access to the values you need
  or
• use TextBox txtBox = (TextBox)myCustomControlObject.FindControl(“nestedTextBox”) method to find (more information here: http://msdn.microsoft.com/en-us/library/486wc64h.aspx)