In your ServiceConfiguration.cscfg file add:
<ServiceConfiguration ... />
<Role ... />
<ConfigurationSettings>
<Setting name="DatabaseConnectionString" value="put your connection string here" />
</ConfigurationSettings>
</Role>
</ServiceConfiguration>
Now you have a connection string you can change by editing the configuration inside the azure portal.
Then anytime you need to retrieve the connection string you can do it using:
using Microsoft.WindowsAzure.ServiceRuntime;
...
String connString = RoleEnvironment.GetConfigurationSettingValue("DatabaseConnectionString")
You may need to add Microsoft.WindowsAzure.ServiceRuntime.dll to your references.
RoleEnviroment.IsAvailable
can be used to test if your are running in Azure, and if not to fall back to your web.config settings.
using System.Configuration;
using Microsoft.WindowsAzure.ServiceRuntime;
...
if (RoleEnvironment.IsAvailable)
{
return RoleEnvironment.GetConfigurationSettingValue("DatabaseConnectionString");
}
else
{
return ConfigurationManager.ConnectionStrings["DatabaseConnectionString"].ConnectionString;
}
This article has a more verbose explanation of the above.