How can I insert data into refrencing table using entity framework

i dont know what you mean when you say
when I'm insert data into into tbl_areaitemmap there is also a insertion in tbl_item and if the item is exist then tbl_areaitemmap refrence to those id.

i have used mapping tables and its meant to be done like this.

first you insert the tbl_item and get its itemid. then insert tbl_area and get its areaid.
then you can add a tbl_areaitemmap with the two ids you just got.

then entity framework will internally link the objects for you by itself.

here is sample

int itemid = 0;
tbl_item tableitem = new tbl_item();
tbl_areaitemmap areaitemmaps = new tbl_areaitemmap();

using(sampleEntities _entitiesContext = new SampleEntities())
{
//setup tableitem values here


//setup tableareaitemmaps values here
areaitemmaps.tbl_area_r.AreaId =7;

//you wont be able to insert a areaitemmap with tbl_itemId of 12 unless
//a tbl_item exists in database with a Id of 12. if you try to add a areaitemmaps
//with tbl_item.Id of a non existing one it will throw a foreign key broken exception
// leave the following line
//areaitemmaps.tbl_item.pkItemId = 12;
areaitemmaps.status = "T";


try
{
//firstly insert the tableitem

_entitiesContext.AddTotbl_item(tableitem);
_entitiesContext.SaveChanges();

//then get the Id of newly inserted tableitem and assign it to the areaitemmap
areaitemmap.tbl_item.pkItemId = tableitem.ItemId

//then insert tableareaitemmap
_entitiesContext.AddTotbl_areaitemmap(areaitemmap);

_entitiesContext.SaveChanges();

//this will make it enforce your foreign key

return true;
}
catch (Exception)
{

return false;
}
}