Question

I have a WCF based webservice and inside the method I am executing a stored procedure and filling dataset then at the end returning the dataset back..like one column and multiple rows. But my requirement is different now as I am calling this webservice through some other product which expects the output based on XML like this. (its a sample XML format) but i want something in the same manner. so how do i generate the xml and return it..I would appreciate if someone can make corrections in the given code as I am not XML guy this is the first time I am going to deal with XML. I would like something

<xml>
   <Approvers>
      <Approver>
          <Approvername>John</Approvername>
      </Approver>
   </Approvers>
</xml>

Sample XML format which i want to follow.

public DataSet getRequisitionApprovers(string pEmail, string pLocationType)
        {
            //Read Datasource properties from Web.config file to access Oracle EBS Database 
            string SDataSource = System.Configuration.ConfigurationManager.AppSettings["SQLDataSource"].ToString();
            string SUserID = System.Configuration.ConfigurationManager.AppSettings["SQLUserID"].ToString();
            string SPassword = System.Configuration.ConfigurationManager.AppSettings["SQLPassword"].ToString();

            //Build connection string based on retrieved parameters from web.config file
            string connectionString = "Data Source=" + SDataSource + ";Persist Security Info=True;" + "User ID=" + SUserID + ";Password=" + SPassword;

            using (SqlConnection connection = new SqlConnection())
            {
                connection.ConnectionString = connectionString;
                connection.Open();

                SqlCommand command = connection.CreateCommand();

                command.CommandType = System.Data.CommandType.StoredProcedure;

                // Name of procedure or function to be execu
                command.CommandText = "Get_RequisitionApprovers";

                command.Parameters.Add(new SqlParameter("theEmail", SqlDbType.VarChar)).Value = pEmail;
                command.Parameters.Add(new SqlParameter("LocationType", SqlDbType.VarChar)).Value = pLocationType;

                //Create New DataSET & DataTable
                DataSet dsApprovers = new DataSet();
                DataTable dtApprovers = new DataTable();

                //Create DataTable Columns and define the data type 
                dtApprovers.Columns.Add("Approver1", typeof(string));


                //Add DataTable to DataSource
                dsApprovers.Tables.Add(dtApprovers);

                SqlDataReader reader = command.ExecuteReader();

                while (reader.Read())
                {
                    //Create new Data Row
                    DataRow theRow = dsApprovers.Tables[0].NewRow();

                    theRow[0] = reader[0].ToString() ;   //Add -> Approver

                    dsApprovers.Tables[0].Rows.Add(theRow);
                }

                return dsApprovers;
            }
        }

Answer 1

As you can see in the video, you’re pretty close to figuring this out.

Make sure you set the DataTable.TableName because if you don’t, it won’t serialize.

All that remains is setting up the WCF Service and defining a WebMethod returning an XML string from your DataTable.

After setting up your WebService, defining a WebMethod and returning the XML goes like this:

//StringWriter requires System.IO
using System.IO;

//This are hypothetical Class and WebMethod names, of course
public class RequisitionApprovers : System.Web.Services.WebService
{
    [WebMethod]
    public string ReturnRequisitionApproversAsXMLString(DataSet ds)
    {
        StringWriter writer = new StringWriter();
        ds.WriteXml(writer, XmlWriteMode.IgnoreSchema);
        string xmlResult = writer.ToString();

        return xmlResult;
    }
}

All that’s left now is to remove the “\r\n” and the whitespaces from the xml string where needed and you end up with a clean xml string to have your WebMethod return.