The type arguments for method cannot be inferred from the usage. Try specifying the type arguments explicitly.

Question

Hi

I have an service that has to LinqToEntitiesDomainService tables in them called towns and buildings. I added an IEnumerable with variables. I now get the following error when I built:

The type arguments for method 'System.ServiceModel.DomainServices.Client.DomainContext.Load<TEntity>(System.ServiceModel.DomainServices.Client.EntityQuery<TEntity>, System.Action<System.ServiceModel.DomainServices.Client.LoadOperation<TEntity>>, object)' cannot be inferred from the usage. Try specifying the type arguments explicitly.

 

My code in the service:

 

public IEnumerable<string> GetStatisticsBuildingsTownTenure(string tableName, string columnName, string ObjectDiscription, string Region, string tenure)
        {

            string connStr = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
            using (var conn = new SqlConnection(connStr))
            using (var cmd = conn.CreateCommand())
            {
                conn.Open();
                string sqlSelect = "";
                if (tableName == "TProperty_Data")
                {
                    sqlSelect = "SELECT DISTINCT  ISNULL(dbo.TProperty_Data.Town, 0) AS Town " +
                                "FROM        dbo.TRegions " +
                                "INNER JOIN  dbo.THead_Property ON dbo.TRegions.Region_Ref = dbo.THead_Property.Region_Ref " +
                                "INNER JOIN  dbo.TProperty_Data ON dbo.THead_Property.Head_Property_ID = dbo.TProperty_Data.Head_Property_ID " +
                                "WHERE     (dbo.TProperty_Data.Town IS NOT NULL) AND dbo.THead_Property.Region_Ref = '" + Region + "' AND Tenure = '" + tenure + "' " +
                                "GROUP BY town";
                }
                else
                {
                    sqlSelect = "SELECT DISTINCT  ISNULL(dbo.TProperty_Data.Town, 0) AS Town " +
                                "FROM        dbo.TRegions " +
                                "INNER JOIN  dbo.THead_Property ON dbo.TRegions.Region_Ref = dbo.THead_Property.Region_Ref " +
                                "INNER JOIN  dbo.TProperty_Data ON dbo.THead_Property.Head_Property_ID = dbo.TProperty_Data.Head_Property_ID " +
                                "INNER JOIN  dbo." + tableName + " ON TProperty_Data.Property_ID = " + tableName + ".PropertyID" +
                                "WHERE     (dbo.TProperty_Data.Town IS NOT NULL) AND dbo.THead_Property.Region_Ref = '" + Region + "' AND " + columnName + " in '" + ObjectDiscription + "' " +
                                "GROUP BY town";
                }

                List<string> strList = new List<string>();

                SqlDataAdapter da = new SqlDataAdapter(sqlSelect, conn);
                DataTable dt = new DataTable();

                da.Fill(dt);

                foreach (DataRow dr in dt.Rows)
                {
                    strList.Add(dr.ItemArray[0].ToString());
                }

                return strList.ToList();
            }
        }

 

My code in my view:

 

LoadOperation<rStatisticsTown> mp = this.stb.Load(this.stb.GetStatisticsBuildingsTownTenure(TableName, ColumnName, ojb, Region, tenure), LoadBehavior.RefreshCurrent, true);

 

This is where my error lies. Please can anyone give any insight.

Thank you

Answer 1

you can change code "return strList.ToList();" to "return strList;"

try, good luck

Answer 2

Hi

Still gives me the same error.

Answer 3

HI,please refer to the code below:

Use [Invoke] attribute to the method.

       
 [Invoke]
        public IEnumerable<string> GetStatisticsBuildingsTownTenure(string tableName, string columnName, string ObjectDiscription, string Region, string tenure)
        {
                List<string> strList = new List<string>();
                for (int i = 0; i < 20; i++)
                {
                    strList.Add(i.ToString());
                }
                return strList.ToList();
        }

 

      
  public MainPage()
        {
            InitializeComponent();
            DomainService1 stb = new DomainService1();
            stb.GetStatisticsBuildingsTownTenure("", "", "", "", "").Completed+=new EventHandler(GetStatisticsBuildingsTownTenure_Completed);
        }
        void GetStatisticsBuildingsTownTenure_Completed(object sender, EventArgs e)
        {
            var list = ((System.ServiceModel.DomainServices.Client.InvokeOperation<System.Collections.Generic.IEnumerable<string>>)(sender)).Value as IList<string>;
        }