Ok ... let's take it from the top.
First, before touching any string of any kind, make sure the solution compiles. Compilation is not dependent upon connection string values. Of course it won't run if they're wrong. But it should compile without errors ... and THAT is step #1.
If you unzipped the package and didn't move anything, all files and directories are where they should be.
Make sure you've got the DevForce directory (holding the DevForce assemblies). That directory must be a sibling of the ModelExplorer2 directory. You'll know it's missing if the links don't work.
Of course if DevForce is installed, this directory becomes irrelevant ... .NET always looks in the GAC for strongly named assemblies.
Everything should compile before you make any changes whatsoever. There is no point in going forward if you can't get it to compile cleanly.
If you've teaked anything, I recommend you unzip again and take it from the top.
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After you have a clean compile, you're ready to connect to the database and the web server.
Please make sure you've attached the NorthwindEF database if you don't already have it as a result of installing a recent version of DevForce. The database included in the package: as .mdf and .ldf files.
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Everyone else listening: you've installed Silverlight 3, right? This only works with Silverlight 3. If you're not sure, contact us.
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Regarding app.config. Unfortunately, there are a bunch of them scattered among the projects. All but one are irrelevant ... you need them only during model development. They have no effect on runtime. Leave them alone for now.
The one that matters at runtime is the one in your Silverlight client project ... ModelExplorer2 in our example. There is no reason to touch this when you're just getting started. I'm assuming you're running with Cassini (the practice web server within Visual Studio), right?
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Which brings us to the Web.config in ModelExplorer2Web.
There is only one reason to go in there when you're starting out. You might have to change the connection string to make it work for the way you installed the NorthwindEF database.
The string you care about in the web.config is in the <edmkey/>. Here's the whole key.
<
edmKey name="Default" connection="metadata=res://ModelExplorer.ServerModelEF/Model1.csdl|res://ModelExplorer.ServerModelEF/Model1.ssdl|res://ModelExplorer.ServerModelEF/Model1.msl;provider=System.Data.SqlClient;provider connection string="Data Source=.;Initial Catalog=NorthwindEF;Integrated Security=True;MultipleActiveResultSets=True"" containerName="ModelExplorer.ServerModelEF.NorthwindEFEntities">
The relevant part of this monster is
provider connection string="Data Source=.;Initial Catalog=NorthwindEF;Integrated Security=True;MultipleActiveResultSets=True"
If you can't reach the database with this string you'll need to find the string that works ... and plunk it carefully in there. If it won't compile, chances are you've done what I usually do ... break something in the XML. Grrr.
Let us know if you're still stuck. -- Ward