Question

Merging data from two lists conditionally

table structure is as following

MobileID   ModelID   ManufacturerID    IsApproved

where IsApproved is boolean value,

When new mobile entry done in database, it goes for the approval to the manager, till that it’s IsApproved value is 0, when it gets approved IsApproved value will become 1.

I want to do as following

I am getting the list of all approved mobile using first query written below

now problem is I have to display all the mobiles based on 2 conditions

1) If a mobile exists with same modelID and manufacturerID (means the specification is updated) than it’s IsApproved field will become 0 –> not in DB but into the list for display purpose only)

2) If Mobile is new than it’s IsApproved status should be 0

What should I do to merge this two lists conditionally?

My LINQ queries are as below

var listApproved = objMobile.MobileLists.where(mb => mb.IsApproved == true).toList();
var listUnApproved = objMobile.MobileLists.where(mb => mb.IsApproved == false).toList();

Suppose table data is as following

MobileID    ModelID     ManufacturerID     IsApproved
01            mod1             manu1               1
02            mod2             manu2               1
03            mod3             manu3               1
04            mod1             manu1               0
05            mod5             manu5               0
06            mod6             manu6               0
07            mod2             manu2               0

I Want the list as

MobileID    ModelID     ManufacturerID     IsApproved
01            mod1            manu1            0
02            mod2            manu2            0
03            mod3            manu3            1
05            mod5            manu5            0
05            mod6            manu6            0

Answer 1

Well, first let’s cache your list in memory to save us getting it more than once:

var listOfAllMobiles = objMobile.MobileLists.ToList();

Now let’s do your logic to get all the mobiles:

var mobileList = listOfAllMobiles
    .Select(m => new Mobile
                 {
                     IsApproved = m.IsApproved == true && !listOfAllMobiles
                         .Any(l => l.ModelID == m.ModelID
                             && l.ManufacturerID == m.ManufacturerID
                             && l.MobileID != m.MobileID),
                     MobileID = m.MobileID,
                     ModelID = m.ModelID,
                     ManufacturerID = m.ManufacturerID
                 })
    .ToList();

EDIT: The above code will set the correct values, but it won’t filter out the mobiles with the duplicate ManufacturerId and ModelID. You’ll have to use an additional foreach for that, like so:

var displayMobileList = new List<Mobile>();

foreach(var mobile in mobileList
    .Where(m => !displayMobileList
        .Any(m2 => m2.ModelID == m.ModelID 
            && m2.ManufacturerID == m.ManufacturerID)))
{
    displayMobileList.Add(mobile);
}