Question

I am trying to set a ViewState-variable when a button is pressed, but it only works the second time I click the button. Here is the code-behind:

protected void Page_Load(object sender, EventArgs e) {     if (Page.IsPostBack)     {         lblInfo.InnerText = String.Format('Hello {0} at {1}!', YourName, DateTime.Now.ToLongTimeString());     } }  private string YourName {     get { return (string)ViewState['YourName']; }     set { ViewState['YourName'] = value; } }   protected void btnSubmit_Click(object sender, EventArgs e) {     YourName = txtName.Text;  } 

Is there something I am missing? Here is the form-part of the design-file, very basic just as a POC:

<form id='form1' runat='server'> <div> Enter your name: <asp:TextBox runat='server' ID='txtName'></asp:TextBox> <asp:Button runat='server' ID='btnSubmit' Text='OK' onclick='btnSubmit_Click' /> <hr /> <label id='lblInfo' runat='server'></label> </div> </form> 

PS: The sample is very simplified, ‘use txtName.Text instead of ViewState’ is not the correct answer, I need the info to be in ViewState.

Answer 1

Page_Load fires before btnSubmit_Click.

If you want to do something after your postback events have fired use Page_PreRender.

//this will work because YourName has now been set by the click event protected void Page_PreRender(object sender, EventArgs e) {     if (Page.IsPostBack)         lblInfo.InnerText = String.Format('Hello {0} at {1}!', YourName, DateTime.Now.ToLongTimeString()); } 

The basic order goes:

• Page init fires (init cannot access ViewState)
• ViewState is read
• Page load fires
• Any events fire
• PreRender fires
• Page renders