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Dynamic connection string

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James Molohon asked on 18 Jan 2011, 05:41 PM

Hello,

I have a Silverlight report viewer to render the report from a class library within the same solution as the Silverlight project, following your best practices guide for creating reports.

In general I need a report to connect to multiple database(s) based on user selected options in a Silverlight application. I also have a Report Parameter which runs a SQL query on the database and returns a list of data that will be used to filter the report data. I’m having difficulty dynamically changing the connection string to the database, the report parameter still points to the initial database set during design time. It seems the report parameter can be accessed only in need_datasource event, but the report parameter needs this connection string to display the list of data that will be used to filter the report data.

1) Is there a way we could set reportParameter AvailableValues.DataSource in the need_datasource event or dynamically.

2) Is there a way to pass this connection string into the constructor in order to set the reportParameter in the constructor. Setting the value here seems to work but I cannot pass a value into the constructor.

3) Is there different design approach that we should be using?

Thanks for your help in advance.

Thanks,
James.

17 Answers, 1 is accepted

answered on 25 Feb 2011, 02:43 AM

What I did is to create a base class inheriting the Report class and use this base class to replace the default base class (Report) for each report. This class contains a public method SetConnectionString which can be called from the show report code.

        private List<SqlDataSource> _sqlDataSources;
        private List<SqlDataSource> SqlDataSources
        {
            get
            {
                if (_sqlDataSources == null)
                    BuildSqlDataSourceList();
                return _sqlDataSources;
            }
        }
        private void BuildSqlDataSourceList()
        {
            _sqlDataSources = new List<SqlDataSource>();
            var fields = GetType().GetFields(BindingFlags.Instance | BindingFlags.NonPublic);
            foreach (var field in fields)
            {
                if (field.FieldType == typeof(SqlDataSource))
                    _sqlDataSources.Add((SqlDataSource)field.GetValue(this));
            }
        }
        public void SetConnectionString(string connectionString)
        {
            foreach (var dataSource in SqlDataSources)
                dataSource.ConnectionString = connectionString;
        }

answered on 28 Mar 2011, 11:25 PM

This is turned into a major issue for us. We need to be able to dynamically change the connection string in our Silverlight apps. For example, each of our customers has multiple databases. Depending on the job they are working on, we want to report based on the correct database. We will only know this at runtime and need to be able to specify the server and the database to run the report. There is no way we can have a connection string for every customer and database in our web.config file. How can I accomplish this?

I posted this last Friday. Should I just send in a support ticked, or start a new thread?

answered on 30 Mar 2011, 06:28 PM

Hi Scott,

As you probably know, there is no Reporting object on the Silverlight client (in the works for subsequent versions) and the reports reside on the server. However you can change the SqlDataSouce.ConnectionString with a Report Parameter:

add a Report Parameter with Visibility set to false
configure your SqlDataSource component as usual
add the following User Function

public static SqlDataSource ChangeConnectionString(object reportItem, string parameterConnectionString)

{

var report = (reportItem as Telerik.Reporting.Processing.Report);

var dataSource = (Telerik.Reporting.SqlDataSource)report.DataSource;

dataSource.ConnectionString = parameterConnectionString;

return dataSource;

}

bind the used data item (Report, Table, Chart).DataSource property with Binding to the =ChangeConnectionString(ReportItem, Parameters.Parameter1.Value)
finally you can set the ReportParameter.Value from Silverlight application as shown in the Programmatic Initialization of Report Parameter Values in Telerik Reporting Silverlight Viewer

Greetings,
Peter
the Telerik team

Vote for the 7 Telerik products at the 2011 Great Indian Developer Awards!

answered on 06 Apr 2011, 09:26 PM

I'm a little confused about how to bind to the DataSource property.
If I go to the Telerik.Reporting.SqlDataSource I'm using. Then look under ConnectionString, it doesn't let me put in an expression like
=ChangeConnectionString(ReportItem, Parameters.Parameter1.Value)
Just that wizard pops up to create a string value.

I put the

public static SqlDataSource ChangeConnectionString 

in my MyReport.cs file  is this correct?


public partial class MyReport: Telerik.Reporting.Report 
{ 
    public MyReport() 
    { 
        // 
        // Required for telerik Reporting designer support 
        // 
        InitializeComponent(); 
        // 
        // TODO: Add any constructor code after InitializeComponent call 
        // 
    } 
    public static SqlDataSource ChangeConnectionString(object reportItem, int zoneNo) 
    {

answered on 21 Oct 2011, 06:29 PM

I just create the connection string with a string value. I have different connection strings saved in my main database table. I'm not sure if this helps you at all.

public static SqlDataSource ChangeConnectionString(object reportItem, int zoneNo, int reportType)

{

var report = (reportItem as Telerik.Reporting.Processing.Report);

var dataSource = (Telerik.Reporting.SqlDataSource)report.DataSource;

dataSource.ConnectionString = DBCalls.getConnectionStr(zoneNo, 3); // This is my personal function to return a string value for a database connection string

return dataSource;

}