Question

I am new to linq.

My code is as below . I need to give the type for results variable. What it should be ?

I tried with assigning results= Enumerable.Emoty<DataRow>(); and casting results to DataRow . But casting failed.

Can anyone tell this?

  var results; 

        if (rbtnSystemTypes.IsChecked == true)
        {
            results = (from DataRow dr in objDataTable.Rows
                       let Markets = dr.Field<bool>("IsActiveMarkets") == true ? "Active" : "Inactive"
                       let Budgets = dr.Field<bool>("IsActiveBudgets") == true ? "Active" : "Inactive"
                       let Programs = dr.Field<bool>("IsActivePrograms") == true ? "Active" : "Inactive"
                       select new
                       {
                           SlNo = objDataTable.Rows.IndexOf(dr) + 1,
                           Country = dr.Field<string>("SystemType"),
                           Market = dr.Field<string>("Market"),
                           ProgramType = dr.Field<string>("JDFType"),
                           Markets = Markets,
                           Budgets = Budgets,
                           Programs = Programs
                       });

        }
        else 
        {
            results = (from DataRow dr in objDataTable.Rows
                       let Markets = dr.Field<bool>("IsActiveMarkets") == true ? "Active" : "Inactive"
                       let Budgets = dr.Field<bool>("IsActiveBudgets") == true ? "Active" : "Inactive"
                       let Programs = dr.Field<bool>("IsActivePrograms") == true ? "Active" : "Inactive"
                       select new
                       {
                           SlNo = objDataTable.Rows.IndexOf(dr) + 1,
                           SubSystemType = dr.Field<string>("SubSystem"),
                           Market = dr.Field<string>("Market"),
                           SystemType = dr.Field<string>("SystemType"),
                           Markets = Markets,
                           Budgets = Budgets,
                           Programs = Programs
                       });
        }

Answer 1

You are creating an anonymous type in your select clauses – these have no specific name (hence anonymous).

Create a class to hold the results and use that as the type in your results.

public MarketData
{
  public int SlNo { get; set; }
  public string SubSystemType { get; set; }
  ...
}

// in the queries:
select new MarketData
{
  SlNo = objDataTable.Rows.IndexOf(dr) + 1,
  ...
}