Check if List with multiple Columns contains string

Question

How do i check if the first column of my list RequirementList contains a string / element

 public class RequirementList
  {
    public string? Name{ get; set; }
    public string? Value { get; set; }
  }

Check here:

var requirementList = new List<RequirementList>();
//requirementList is already filled

  if(requirementList.Name.Contains("Test"))
{
     //do something
}

By column, do you mean the first property in the RequirementList object? — Piotr Szuflicki, Apr 21 '22 at 08:25
Maybe a matter of personal taste, but in my opinion it seems counter-intuitive to name the class Requirement*List* when the usage is *list item*. The term List tells me you are referring to a collection of items. — soupy-norman, Apr 21 '22 at 09:10

score 3 · Answer 1 · answered Apr 21 '22 at 08:26

Considering that Name can be null here, you should do it like this:

if(requirementList.Any(x=>x.Name is not null && x.Name.Contains("Test"))

Note that Contains here will be case sensitive. You can check this answer to handle case insensitivity Case insensitive 'Contains(string)'

score 0 · Answer 2 · answered Apr 21 '22 at 09:38

0

to complete or give another flavor with a modern c# you can write this as

if(requirementList.Any(x=>x?.Name.Contains("Test") ?? false)

answered Apr 21 '22 at 09:38

user2147873

107
5

score 0 · Answer 3 · answered Apr 21 '22 at 10:50

You seem to have some misconceptions around lists and properties, so I'll try to make it a little more clear. Some of this has been mentioned by others.

First, don't call something list, if it isn't a list. RequirementList should be called RequirementItem or just Requirement.

Now your definition looks like this:

var requirementList = new List<Requirement>();

See, it's already more logical.

Second, Name and Value are properties of a Requirement, they are not columns and you shouldn't think of them as such. Hence first doesn't apply, there is no first property

public class Requirement
{
    public string? Name{ get; set; }
    public string? Value { get; set; }
}

is equivalent to

public class Requirement
{
    public string? Value { get; set; }
    public string? Name{ get; set; }
}

And finally it looks like you want do something special to requirements with test in the name, so you should select the requirements first:

var requirementList = new List<Requirement>();
...
var testRequirements = requirementList.Select(x=>x?.Name.Contains("Test"));
if (testRequirements.Any())
{
    foreach (var req in testRequirements)
    {
        // do something with req
    }
}

This saves you the trouble of doing Any first and then select the ones you need to work with.

Check if List with multiple Columns contains string

3 Answers3