Solved

c# linq group labmda expression null issue

Posted on 2015-02-16
2
106 Views
Last Modified: 2015-03-03
I have a collection that I am trying to group on.  If this statement does not return a value, I am trying to set the column to 0, but the group returns no results.
 whatIfScenarios.Find(x => x.CbiId == g.First().CbiId && x.Type == WhatIfScenarioType.Plan).WhatIfOutput.RiskMarkScore

here is my code

var group = (from r in riskMarkOutputModel.Recommendations
    where r.InPlan == true
    group r by r.CbiId
    into g
    select
        new
        {
            IndexRecNum = g.First().IndexRecNum,
            a = whatIfScenarios.Find(x => x.CbiId == g.First().CbiId && x.Type == WhatIfScenarioType.Plan).WhatIfOutput.RiskMarkScore ?? 0/*,

Open in new window



If I leave out the row "a", I get a group.  If I leave "a" in, the group is empty.  Even if the find is blank, I want the group to show.
0
Comment
Question by:jackjohnson44
2 Comments
 
LVL 11

Accepted Solution

by:
louisfr earned 500 total points
ID: 40630064
If Find returns null, you'd get an exception when trying to retrieve the WhatIfOutput property. Unless you're using C# 6, you need to check that before trying to access the property.
var group = (from r in riskMarkOutputModel.Recommendations
             where r.InPlan == true
             group r by r.CbiId
             into g
             let scenario = whatIfScenarios.Find(x => x.CbiId == g.First().CbiId && x.Type == WhatIfScenarioType.Plan)
             select
                 new
                 {
                     IndexRecNum = g.First().IndexRecNum,
                     a = scenario == null ? 0 : scenario.WhatIfOutput.RiskMarkScore
                 }

Open in new window

0

Featured Post

Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

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

Suggested Solutions

Title # Comments Views Activity
How to repeat the data 4 30
ASP.NET Built-In Report Creator / Viewer 5 23
Web page design problem 3 17
Inserting LocalDB Table to SQL Server C# 3 18
Many of us here at EE write code. Many of us write exceptional code; just as many of us write exception-prone code. As we all should know, exceptions are a mechanism for handling errors which are typically out of our control. From database errors, t…
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…

733 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