Connect to Microsoft SQL Server 2012 with WCF web service

I am trying to connect an Microsoft SQL Server 2012 database to an Xamarin.Android app.

As internet researches told me that it is not possible to connect directly to an external database in Xamarin and that I need a layer between my app and the database, I tried to implement that needed WebService with the help of
https://www.youtube.com/watch?v=xnO9MbferQo

Unfortunately, when I try to run (pressing F5 in Visual Studio) this web service, he opens the WCF-TestClient (as it should be), but after maybe after half of the progress bar ("is adding"), an error view is showed, saying:

Warnung: Es wurde kein Code generiert. Wenn Sie versucht haben, einen Client zu generieren, könnte die Ursache hierfür sein, dass die Metadatendokumente keine gültigen Verträge oder Dienste enthielten oder dass erkannt wurde, dass sich alle Verträge/Dienste in /reference-Assemblys befinden. Stellen Sie sicher, dass alle Metadatendokumente an das Tool übergeben wurden. Warnung: Wenn Datenverträge aus Schemas generiert werden sollen, müssen Sie sicherstellen, dass die Option /dataContractOnly verwendet wird.

Sorry for this German. I try to translate it for you:

Warning: No code has been generated. If you tried to generate a client, a possible reason for this could be, that the meta data documents do not contain valid contracts or services or that all contracts/services are lying in /reference-Assemblys. Please make sure, that all meta data documents are transfered to the tool.
Warning: If data contracts are generated from a schema, you have to make sure, that the option /dataContractOnly is used.

Please let me share my code:

Service1.svc.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;
using System.Data;
using System.Data.SqlClient;
namespace TestWcfService
{
public class Service1 : IService1
{
// Connection string
private readonly string conStr = "data source = [Server-IP]\\[instance_name]; initial catalog = [catalog_name]; user id = [dbusername]; password = [dbpw]; Connect Timeout = 60"";
public List GetAdrSuche1()
{
List adrList = new List();
SqlConnection con = new SqlConnection(conStr);
con.Open();
SqlCommand cmd = new SqlCommand("SELECT * FROM adressen", con)
{
CommandType = CommandType.Text
};
SqlDataReader reader = cmd.ExecuteReader();
while (reader.Read())
{
AdrSuche1 adrSuche1 = new AdrSuche1
{
Adrsuche1 = reader["adrsuche1"].ToString()
};
adrList.Add(adrSuche1);
}
return adrList.ToList();
}
}
}

IService1.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Web;
using System.Text;
namespace TestWcfService
{
public interface IService1
{
[OperationContract]
[WebGet(UriTemplate = "GetAdrSuche1")]
List GetAdrSuche1();
}
[DataContract]
public class AdrSuche1
{
string adrsuche1;
[DataMember]
public string Adrsuche1
{
get { return adrsuche1; }
set { adrsuche1 = value; }
}
}
}

What is the problem? Can anyone maybe help me integrating Web Api or WCF Service so I can read data from external database and display them on my app?

Best regards

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Ahsan Siddique8y ago
Accepted answer
Hi, Please follow these tutorials.

Developing RESTful API in ASP.Net With Azure Database and you also use your local database.

Part 1
https://c-sharpcorner.com/article/creating-sql-database-in-azure-portal/

part 2
https://c-sharpcorner.com/article/developing-restful-api-in-asp-net-with-add-method/

Part 3
https://c-sharpcorner.com/article/developing-restful-apis-in-asp-net-with-retrieve-update-and-delete-functions/

Consuming RESTful API in Xamarin.Android

part 4
https://c-sharpcorner.com/article/consuming-restful-apis-in-xamarin-android/
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Sam Mettenmeyer8y ago
Hello and sorry that I write again,

I have now gone through every tutorial you recommended.

Unfortunately, when trying to run the application of video #4, he get's an error in the building process saying

"String types not allowed (at 'layout_marginTop' with value '10db'). (File: DeleteFeedback.axml, Line 2)"

Do you maybe know what's wrong? i have completely same code as in the video.

Best regards
0
Ahsan Siddique8y ago
If you already have a database then you just need to develop a RESTful API that will perform oprations that's you want. Please skip my first video and follow the 2nd video. In the fourth video you will see how to consume RESTful API in Xamarin.
0
Sam Mettenmeyer8y ago
Hello Ahsan,

thank you for your reply.

Unfortunately, you got me a little wrong:

I do not want to create a new database (particularly to use Azure database as expected, a payment is required, or at least by signing up one has to give credit card data which I don't have).

I have an existing database given by my employer which runs on Microsoft SQL Server 2012 and need to connect / read from this.
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