?
Solved

Questions Tags Users Badges Unanswered Ask Question

Posted on 2011-09-15
1
Medium Priority
?
49,103 Views
Last Modified: 2012-05-12
I have the following datatable, which has Units information. The Units have a surface in square meters. However the units can be split into subunits, in the datatable there is a ParentUnitID to know if that unit is splitted or not.

I need to validate that the sum of the surface of the child units, is equal to the surface of the parent unit.

 bWJwN.png

In anoter forum they helped me with this code


 var childrenByParentID = _unitDataSet.Unit.AsEnumerable().
                                     GroupBy(child => child.Field<int?>("ParentUnitId")).
                                     ToDictionary(group => group.Key);

            // Parents = children with no parent
            var parents = childrenByParentID[null];

            // Look for the first group which sum of surfaces is not the same as the parent's surface
            var invalidGroup = childrenByParentID.FirstOrDefault(group =>
            {
                bool invalid = false;

                if (group.Key != null)
                {
                    // Not the parents group
                    var parent = parents.Single(parent => parent.Field<int>("UnitID") == group.Key);

                    var totalSurface = group.Sum(group => group.Field<int>("Surface"));
                    invalid = (totalSurface != parent.Field<int>("Surface"));
                }

                return invalid;
            });

            if (invalidGroup != null)
            {
                // .. do something special
            }

Open in new window


However I got this error.

 dlaxL.png
0
Comment
Question by:Simbios
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 4

Accepted Solution

by:
guramrit earned 2000 total points
ID: 36541297
There're some common mistakes in this code. You've to change it->

change
  var parent = parents.Single(parent => parent.Field<int>("UnitID") == group.Key);
to
  var parent = parents.Single(p => p.Field<int>("UnitID") == group.Key);

change
    var totalSurface = group.Sum(group => group.Field<int>("Surface"));
to
    var totalSurface = group.Sum(g => g.Field<int>("Surface"));

last thing, you cannot compare object of KeyValuePair<,> with null, because its a Structure (valuetype) returned by following code
   invalidGroup = childrenByParentID.FirstOrDefault ......

try using ToLookup instead of ToDictionary

0

Featured Post

Want to be a Web Developer? Get Certified Today!

Enroll in the Certified Web Development Professional course package to learn HTML, Javascript, and PHP. Build a solid foundation to work toward your dream job!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

IntroductionWhile developing web applications, a single page might contain many regions and each region might contain many number of controls with the capability to perform  postback. Many times you might need to perform some action on an ASP.NET po…
It was really hard time for me to get the understanding of Delegates in C#. I went through many websites and articles but I found them very clumsy. After going through those sites, I noted down the points in a easy way so here I am sharing that unde…
Add bar graphs to Access queries using Unicode block characters. Graphs appear on every record in the color you want. Give life to numbers. Hopes this gives you ideas on visualizing your data in new ways ~ Create a calculated field in a query: …
Have you created a query with information for a calendar? ... and then, abra-cadabra, the calendar is done?! I am going to show you how to make that happen. Visualize your data!  ... really see it To use the code to create a calendar from a q…
Suggested Courses

764 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question