why i can't view my listview on runtime

protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
           
        }
    }

// Here i used ItemCommand EVENT
// and above code i want to use in page load Event  

    protected void gvUserInfo_ItemCommand(object sender, ListViewCommandEventArgs e)
    {
                
        DataTable dtchildpin = (DataTable)Session["dtchildpin"];
        Label pin = (Label)e.Item.FindControl("lblpin");
        dtchildpin = DAL.Sent_SmartPin.View(pin.Text.ToString());
        gvUserInfo.DataSource = dtchildpin;
        gvUserInfo.DataBind();
    }