How to avoid the button events on Refresh of page

Question

I have .aspx page that page inserts the data to the database on a button click. But when i press the button it is going right. i m getting the Successfully message as " successfully inserted data". In this situation if i press "F5" or Refresh the page it is firing the button click event. Why it should be ? How to avoid this condition ?

Answer 1

When the user clicks F5 (or uses a toolbar button to refresh the page) it will cause a new request, identical to the previous one, to be sent to the server. The Button.Click event will be raised again, but you have a few ways to protect yourself against inserting the data twice.

The best way, IMHO, is to use the Post/Redirect/Get pattern. In your code, right after the point where the data is saved, do a 302 redirect to a confirmation page:

protected void btnSaveStuff_Click(object sender, EventArgs e)
{
    SaveStuffToDatabase();
    Response.Redirect("confirmation.aspx");
}

When using the pattern, the POST to the original page will not end up in the browser history, and refreshing the result page will cause the final GET to be repeated, which should be safe.

Answer 2

Add this in your class:

#region Browser Refresh
private bool refreshState;
private bool isRefresh;

protected override void LoadViewState(object savedState)
{
    object[] AllStates = (object[])savedState;
    base.LoadViewState(AllStates[0]);
    refreshState = bool.Parse(AllStates[1].ToString());
    if (Session["ISREFRESH"] != null && Session["ISREFRESH"] != "")
        isRefresh = (refreshState == (bool)Session["ISREFRESH"]);
}

protected override object SaveViewState()
{
    Session["ISREFRESH"] = refreshState;
    object[] AllStates = new object[3];
    AllStates[0] = base.SaveViewState();
    AllStates[1] = !(refreshState);
    return AllStates;
}

#endregion 

And in your button click do this:

protected void Button1_Click(object sender, EventArgs e)
{
    if (isRefresh == false)
    {
        Insert Code here