C#

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.

RadGrid and grouping message

Alex Bransky — Thu, 27 Dec 2007 00:06:35 GMT

If you're using telerik's RadGrid and you're seeing a message in the UI that says "Drag a column header and drop it here to group by that column" and you want to hide that message, here's what you do:

myRadGrid.GroupPanel.Text = "";

This page just confused me rather than helping me:

http://www.telerik.com/community/forums/thread/b311D-mdedg.aspx

AJAX: Unknown server tag 'asp:ScriptManager'.

Alex Bransky — Wed, 16 May 2007 23:54:01 GMT

I just spent an unhealthy amount of time trying to figure out this error:

Unknown server tag 'asp:ScriptManager'.

I was baffled because I already had a reference to AjaxControlToolkit.dll in my project, and I had what I thought was a web.config ready to handle any AJAX requests. It turned out adding the section below to system.web fixed the problem.

<pages>

</controls>

</pages>

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?

SqlBulkCopy

Alex Bransky — Wed, 11 Apr 2007 10:06:00 GMT

I just discovered the SqlBulkCopy class in .Net 2.0, and it seems awesome! Now I don't have to shell out to BCP anymore! We'll see though, I haven't done any performance testing yet...

settings transfer from designer to code in composite control in asp.net

Alex Bransky — Wed, 04 Apr 2007 07:05:00 GMT

If you want to build your own composite control for ASP.Net and you want to create in such a way that when you set a property in the designer window, the setting is reflected in the aspx code, placing this attribute on each public property is the key:

[DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]

getting web app assembly from composite control

Alex Bransky — Fri, 16 Mar 2007 07:45:00 GMT

If you have a composite control you've created for use in ASP.Net, and you want to use that control to display the name and version of the web application's assembly, there's something you need to know: As far as I can tell, there's no way to get the correct assembly if you're only embedding the control in the HTML code. In this case, GetCallingAssembly() returns System.Web rather than the app name. But if you add the control from the codebehind, or if you add a method to the control that gets called on Page_Load() from the ASP.Net page, then you will get the app name and version you're looking for, presumably because the calling assembly returned by GetCallingAssembly() is the web app assembly.