Cannot convert list to model

Question

Hi,

I am trying to bind a model to an select element in Blazor /.net 5. I already have one that reads a json file and that works fine but this one I am trying to get the data from a database. The problem comes when I try and get the DataTable into my Model. So I created a List<Model> and am trying to get it into my model. I am getting "cannot convert type list<model> to model" error. I have also tried a foreach item in list, add the item (note commented out section) but that is giving an NullReference error on the USStates.States even though I have a "new" on the model (StatesModel).

Can anyone tell me how to do this correctly? Help Appreciated..Thanks...

private StatesModel USStates { get; set; }

private Task GetStatesModel()
{
DataTable dt = new DataTable();
SQL.GetSQLData exe = new SQL.GetSQLData();
dt = (DataTable)exe.GetValues("storedProcName", "ConnStringName");

List<StateModel> StateList = Data.Conversion.ConvertDataTabletoModel.ConvertToList<StateModel>(dt);

USStates = StateList; --- Cannot Convert list<statemodel> to statemodel

//foreach (var item in StateList)
//{
// USStates.States.Add(item); -- Null Reference exception.
//}

return Task.CompletedTask;
}

and my Model......

public class StatesModel
{
public List<StateModel> States { get; set; } = new List<StateModel>();
}

public class StateModel
{
public string StateName { get; set; }
public string StateAbbreviation { get; set; }
}

---------------------------------------------------------------------------------------------------

FYI I also tried this USStates.States = StateList; - and I get a null reference exception at runtime on this line.

Jignesh Kumar · Answer

ok, Your issue is resolved right ? or you need more help on this.

David Smith · Answer

So, My problem ended up being in the UI. This actually works.... (dt is the datatable from SQL) USStates.States = Data.Conversion.ConvertDataTabletoModel.ConvertToList (dt); Then changed the .razor component to Select State @if (USStates.States != null) { @foreach (var item in USStates.States) { @item.StateAbbreviation } } ------------------------------------------------------------------ from this..... Select State @if (USStates.States != null) { @foreach (var item in USStates.States) { @item.StateAbbreviation } }

David Smith · Answer

Hi, Thanks but this does not work for me. If you notice my first line of code. private StatesModel USStates { get; set; } that is the USStates that binds to the .razor select control. So using a var USStates later on in the code does not work. --Please choose a state-- @foreach (var item in USStates.States ) { @item.StateName }

Jignesh Kumar · Answer

Hi, You are trying to map two different model. Please try this one, private Task GetStatesModel() { DataTable dt = new DataTable(); SQL.GetSQLData exe = new SQL.GetSQLData(); dt = (DataTable)exe.GetValues("storedProcName", "ConnStringName"); List StateList = Data.Conversion.ConvertDataTabletoModel.ConvertToList (dt); var USStates = new List (); //If you need only US records then you need to filter your List here StateList = StateList.Where(x => x.StateName == "United States").ToList() USStates.AddRange(StateList); return Task.CompletedTask; } public class StatesModel { public List States { get; set; } = new List (); } public class StateModel { public string StateName { get; set; } public string StateAbbreviation { get; set; } }

Cannot convert list<model> to model