Try with below processes:
Through
entity Entity SQL:
string sqlString = "SELECT VALUE st FROM CoffeeShopDBEntities.tblProduct AS st WHERE st.ProductType == '" + cboProductType.SelectedValue+ "'";
var objctx = (ctx as IObjectContextAdapter).ObjectContext;
ObjectQuery<tblproduct> filteredProducts = objctx.CreateQuery<tblproduct>(sqlString);
</tblproduct></tblproduct>
Through
Native SQL:
using (var ctx = new CoffeeShopDBEntities())
{
var filteredProducts = ctx.tblProduct.SqlQuery("select value product from tblProduct as product where product.ProductType = '" + cboProductType.SelectedValue + "'").ToList<tblproduct>();
}
</tblproduct>
Note: Above code written as assuming the entity name as tblProduct. If it is different like "Products" in EF then change it.