Comments by Balimusi (Top 13 by date)

Ok, I see the extra tick mark and removed it. I was typing it here, and didn't test the code in Management Studio.

Anyhow, you can return the data to your GridView using DataTable. And then bind it the GridView; for instance, GridView1.DataSource = dataTable1; GridView1.Bind();

Try this - http://pluralsight.com/training

There are tons of materials out there on the Internet on how to implement a Web service. In fact, I have an article on basic WCF implementation. You can also download the source code and play around with it. It was developed using VS2012, but you can still open it using VS2010. Check it out: http://www.codeproject.com/Articles/581273/WCF-4-5-Services-Development-with-Entity-Framework

You can use a GridView that is nested inside of a DataList. Let the DataList be the container of the Category and place the Sub-category data inside the GridView.

Try adding the baseAddress; for instance,
<host>
<baseAddresses>
<add baseaddress="http://localhost:8733/Design_Time_Addresses/WcfService1/Service1/">
</baseAddresses>
</add>
</host>

Yes, replace that Console.WriteLine() and write it to a file and that is stored in your drive.

Btw, I have an article on WCF service, there is an example using a class properties to hold the data and return a generic List<>. http://www.codeproject.com/Articles/581273/WCF-4-5-Services-Development-with-Entity-Framework

Yes, of course is possible. Do something like this:
private ArrayList getItemsFromListView()
{
MyWebService.DataServiceClient client = new MyWebService.DataServiceClient();
//Get your ListView listViewFromService;
ListView listView = client.ListViewFromService();
ArrayList arrayList = new ArrayList();

foreach (ListViewItem itemRow in this.listView.Items)
{

for (int i = 0; i < itemRow.SubItems.Count; i++)
{
arrayList .Add(itemRow.SubItems[i].Text);

}
}
return arrayList ;
}