title: Asp.Net on refresh, a duplicate post is inserted...should only be one post
body: <p>I have a asp:textbox that allows a user to enter information. When the user clicks the asp:button, it inserts the text from the textbox into my sql database, and then redirects back to the page. If the user hits refresh, the event from the button gets called again. I need to rectify this so that it no longer gets called or it doesn't repost the information.    </p>
  
  <pre><code>protected void PostButton_Click(object sender, EventArgs e)
  {
      if (txtWallPost.Text.Length &gt; 0)
      {
          string strCon = System.Web.Configuration.WebConfigurationManager.ConnectionStrings["SocialSiteConnectionString"].ConnectionString;
          using (SqlConnection conn = new SqlConnection(strCon))
          {
              using (SqlCommand cmd = conn.CreateCommand())
              {
                  cmd.CommandText = "INSERT INTO [WallTable] ([UserId], [FriendId], [WallPost]) VALUES (@UserId, @FriendId, @WallPost)";
                  cmd.Parameters.AddWithValue("@UserId", User.Identity.Name);
                  cmd.Parameters.AddWithValue("@FriendId", User.Identity.Name);
                  cmd.Parameters.AddWithValue("@WallPost", txtWallPost.Text);
                  conn.Open();
                  cmd.ExecuteNonQuery();
                  conn.Close();
                  txtWallPost.Text = "";
                  LoadWallPosts();
                  Response.Redirect("~/UserPages/UserProfile.aspx?view="+"wall");
              }
          }
      }
      return;
  }
  </code></pre>