general .Net stuff

ajax loader in user control within master page

Alex Bransky — Thu, 09 Apr 2009 16:58:45 GMT

I spent hours trying to figure out why my ASP.Net page, which uses a master page with a RadGrid surrounded by a RadAjaxPanel with an AjaxLoadingPanel, would not show the loading message. I would click on the link to the page in the site menu, then IE would sit and spin for a while until it loaded the entire page, rather than loading the page right away but showing the loading spinner until the data was returned. What I had to do was add this javascript (w/jQuery) to the user control that the grid was in:

    function loadGrid() {
        window['<%=RadAjaxPanel1.ClientID %>'].AjaxRequest('');
    }
</script>

I'm not sure why I had to make it sleep for half a second, but it wouldn't work until I added that.

I set up a server-side event (OnAjaxRequest="RadAjaxPanel1_AjaxRequest") that fires when AjaxRequest is called in the javascript:

protected void RadAjaxPanel1_AjaxRequest(object sender, AjaxRequestEventArgs e) {
Presenter.InitializeView();
BindGrid();
}

tinyint surprise

Alex Bransky — Wed, 11 Feb 2009 01:05:03 GMT

I just discovered something rather surprising. If you return a tinyint from a stored procedure as part of a dataset, and bind that dataset to a dataview, and then do something like this:

<asp:Label runat="server" id="statusLabel" Text='<%# GetStatusText( (int)DataBinder.Eval(Container, "DataItem.status")) %>'>
</asp:Label>

You will get an error about an invalid cast. If the stored procedure returns an int instead of tinyint, it works just fine. How can ASP.Net 3.5 not be able to cast from a tinyint (or whatever its C# equivalent is) to an int??

resharper and auto-property gotcha

Alex Bransky — Thu, 07 Aug 2008 23:10:29 GMT

Be very careful when allowing Resharper to convert properties to auto-properties. In some cases it will re-initialize fields that were already initialized earlier on in the constructor.

http://www.jetbrains.net/jira/browse/RSRP-75137;jsessionid=D915EE10CA08D52D70BCAD44AE37447B?page=com.atlassian.jira.plugin.system.issuetabpanels:changehistory-tabpanel

generic typing and scope_identity()

Alex Bransky — Wed, 06 Aug 2008 17:38:38 GMT

I recently ran into an interesting problem. I had created a data access method that used generic typing to execute a scalar SQL Server stored procedure (below), and in the stored procedure was returning SCOPE_IDENTITY() for an integer identity column. I was passing in a type of "int" to the method (as <T>) since that's what I was expecting back, but I kept getting back null. After some frustration and bewilderment I discovered that SCOPE_IDENTITY() always returns a decimal, and C# doesn't want to convert the decimal to an integer automatically. I worked around it by using CAST in the stored procedure so that I didn't have to modify the method.

        private static T? ExecuteScalarStoredProcedure  (string sprocName, SqlParameter[] parameters) where T : struct {

            SqlConnection conn = new SqlConnection(GetConnectionString());

            conn.Open();
            object retValue;
            try {
                SqlCommand command = new SqlCommand(sprocName, conn);
                command.CommandType = CommandType.StoredProcedure;
                command.Parameters.AddRange(parameters);

                retValue = command.ExecuteScalar();
            }
            finally {

                try {

                    conn.Close();

                }
                catch (Exception) {
                    //Ignore close exception
                }
            }
            return retValue as T?;
        }

activerecord and executereader exceptions

Alex Bransky — Wed, 28 May 2008 20:46:45 GMT

About once a day I was getting the following error from an ASP.Net web page that uses ActiveRecord:

Exception Details: System.Data.SqlClient.SqlException: A transport-level error has occurred when sending the request to the server. (provider: TCP Provider, error: 0 - An existing connection was forcibly closed by the remote host.)

I would subsequently get this error upon refreshing the page:

Exception Details: System.InvalidOperationException: ExecuteReader requires an open and available Connection. The connection's current state is closed.

I finally figured out that the problem occurs when the database is restored. The connections in the IIS application pool do not get destroyed when the database is restored, so when ActiveRecord (nHibernate) tries to reuse the connections it fails. This doesn't happen to me when I'm not using ActiveRecord, so I'm not sure if this is a bug with ActiveRecord or a problem with the way I've set up the data access layer.

granularity error in SSAS MDX drillthrough query

Alex Bransky — Wed, 09 Apr 2008 22:44:14 GMT

I was trying to create an MDX drillthrough this morning in my SSAS 2005 cube, and I got this error:

Errors from the SQL query module: The attribute 'Applicant Name' in the dimension 'Dim Candidate' is outside the granularity of the measure group 'Fact Requisitions' and cannot be returned as a column.

I only got one result from Google for that error message and it wasn't helpful at all. After trying a million different things with partitions and actions and whatnot, I finally figured out the problem: I was trying to return drillthrough data from a fact table other than the one containing the default measure. Once I threw in a measure (in the SELECT part of the query, not the RETURN) from the non-default fact table, everything worked great!

CPU percent limit in .Net

Alex Bransky — Fri, 01 Feb 2008 23:29:37 GMT

Why doesn't the .Net framework have anything that lets you set a maximum CPU usage for an application? Is it something Windows can't handle? I'd really like to be able to say, "I don't care if this app gets stuck in a loop or whatever, it will never get above 25% CPU."

fastest way to show SQL data in a web page

Alex Bransky — Wed, 21 Nov 2007 23:45:09 GMT

I'm curious what people think is that fastest way to show SQL Server data in a web page. Assuming you create the virtual web in IIS yourself, I'm hoping somebody knows of something that lets you create an xml file with connection settings and a query file, then the product automagically puts the data in a grid on the web page. Granted once you're used to Visual Studio it doesn't take terribly long to do such a thing, but I'd still like something faster, maybe something that can automagically create graphs too.

ajax rocks

Alex Bransky — Tue, 09 Oct 2007 17:24:40 GMT

I now believe that anyone who is developing an ASP.Net application and is not in an extreme time crunch is crazy not to use Ajax.

serial for dinner and a cookie for dessert

Alex Bransky — Tue, 15 May 2007 16:11:48 GMT

Can anybody explain serializability to me? Can any class be made serializable, but it's just better not to for some?