public class PageControlsM
    {

        [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }

        public string ControlCode { get; set; }

        [ForeignKey("ControlCode")]
        public  ControlTypes ControlTypes { get; set; }

    }

public class ControlTypes
    {
        [Key]
        public string Code { get; set; }
        
        public string ControlName { get; set; }

        public string HtmlCode { get; set; }
    }

 <TelerikGrid Data="@PageControlList"
                  Height="auto"
                  Pageable="true"
                  Sortable="true"
                  Reorderable="true"
                  Resizable="true"
                  PageSize="5"
                  EditMode="GridEditMode.Popup">
            <GridToolBar>
                <GridCommandButton Command="Add" Icon="add">Yeni Kontrol Ekle</GridCommandButton>
            </GridToolBar>
            <GridColumns>

                <GridColumn Field=@nameof(PageControlsM.ControlCode) Width="100%" Title="Kontrol Turu">
                    <EditorTemplate Context="controlMContext">
                        @{
                                if (controlMContext is PageControlsM controlM)
                                {
                                <TelerikComboBox Data="@ControlTypesList"
                                                 TextField="ControlName"
                                                 ValueField="Code"
                                                 Width="90%"                                                
                                                 @bind-Value="controlM.ControlCode"
                                                 Placeholder="<Seciniz>"
                                                 ClearButton="true"
                                                 Filterable="false">
                                </TelerikComboBox>
                                }
                        }
                    </EditorTemplate>

                </GridColumn>

                <GridCommandColumn Width="100%">

                    <GridCommandButton Command="Edit" Icon="edit">Edit</GridCommandButton>
                    <GridCommandButton Command="Delete" Icon="delete">Delete</GridCommandButton>
                    <GridCommandButton Command="Update" Icon="update" ShowInEdit="true">Update</GridCommandButton>

                    <GridCommandButton Command="Save" Icon="cancel" ShowInEdit="true">Save</GridCommandButton>
                    <GridCommandButton Command="Cancel" Icon="cancel" ShowInEdit="true">Cancel</GridCommandButton>
                </GridCommandColumn>

            </GridColumns>

        </TelerikGrid>

<TelerikComboBox @bind-Value=_selectedValue Data="@myComboData" TextField="MyTextField" ValueField="MyValueField" TValue="int" TItem="MyDdlModel">
</TelerikComboBox>

@code {
	int _selectedValue { get; set; } = 2; // Preselected value
	IEnumerable<MyDdlModel> myComboData { get; set; } = Enumerable.Empty<MyDdlModel>();

	protected override async Task OnInitializedAsync()
	{
		myComboData = await LoadData();
		await base.OnInitializedAsync();
	}

	private async Task<IEnumerable<MyDdlModel>> LoadData()
	{
		await Task.Delay(1);
		return Enumerable.Range(1, 20).Select(x => new MyDdlModel { MyTextField = "item " + x, MyValueField = x });
	}

	public class MyDdlModel
	{
		public int MyValueField { get; set; }
		public string MyTextField { get; set; }
	}
}