First, I want to apologize to the three people that read my blog. Sorry for going dark for such a long period of time. I am not going to commit to writing on a regular basis just yet, but I will be back consistently soon. Enough about me, let’s talk about the problem at hand. Recently, someone asked if it was possible to show column information (description, data type, etc…) in a tooltip. I never really gave that scenario much thought until I was posed with the question. So, is it possible in SSRS 2008 R2? The answer is, not natively. However, it can be done with a little effort.

Report Code

Assuming you have already created your report, the first step is to add some custom code to your report. To do this click Report on the menu bar and select Report Properties. The Report Properties dialogue window will open.

Select the item labeled Code in the left section of the window. In the textbox labeled Custom Code, type your code. In the above image I included a VB code snippet that accepts two parameters, ColumnName and TableName. The code executes a query that returns the data type for the column/table combination. The statement could be modified to query a Meta data repository that contains more descriptive information about your column. For the sake of brevity I am querying the information_schema.columns table. Once you have written your custom code, the next step is to add a reference to the System.Data assembly. To do this, select References in the left section of the Report Properties window.

Next click the button labeled Add under Add or remove assemblies. Click the Ellipses button located to the newly added textbox and the Add Reference dialogue window will open.

Ensure that the .NET tab is selected, scroll down the list until you see System.Data. Select it and click OK.

The ToolTip

With all of the plumbing in place, now it’s time write the expression that will execute the code and render the tooltip. Since the requirement is to surface information about columns in the data set I will be adding an expression to the tooltip for each column header in the table on my report. To quickly apply the expression to each column, select every applicable column header in your table and press the F4 key, which opens the Properties window. Locate the ToolTip option, click in the field, select the drop down arrow and choose Expression. In the expression window type the following:

=Code.GetMetaData(Replace(ReportItems!Textbox5.Value,” “,“”), “Product”)

As mentioned above, the function accepts two parameters. The first is the value of that is displayed in the column header. Since SSRS automatically adds a space to column names that contain upper case letters, I used the Replace function to remove the spaces. One caveat about this approach is that if you customize the column header names you will need to explicitly include the column name in the expression instead of the code that I have include for the first parameter. The second value is the table name. You could further extend this to include the schema name also.

Security

After all that I really really really thought I was done. So, I ran the report and when I hovered over my column headers nothing happened. To be honest, I had no idea what to do. After a few minutes of thinking I remember that there was an Output window available when you ran reports. I clicked View on the menu bar and selected Output, and there was my error:

‘Textbox5′ contains an error: Request for the permission of type ‘System.Data.SqlClient.SqlClientPermission, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089′ failed.

Since I am not much of a .Net developer, I was still pretty lost. I decided to start searching the Internet. I found a few articles that evenutally led me a config file that needed to be modified. While I was pointed to the correct file, neither of documents provided me with the specific solution. After making a few changes and a few undo’s my report ran successful.

In this directory, C:\Program Files (x86)\Microsoft Visual Studio 9.0\Common7\IDE\PrivateAssemblies, open the RSPreviewPolicy file. Locate the first CodeGroup section, which will be directly below the closing NamedPermissionSets tag, change the PermissionSetName attribute to FullTrust and save the file. You may want to make a copy of the file prior to changing and saving it.

After this change has been made, save the file and preview your report, which should run now.

If you have a better solution for this, please send me an email at pleblanc@sqllunch.com. Also, if something does not work send me an email. Thanks for reading.

Talk to you soon,

Patrick LeBlanc