A better way than if/else to check index array

Question

I am geting an index out of bounds error, I understand why I am getting it. What I am looking for is perhaps some features of c# I may not be aware of instead of using a bulky if/else statement.

If the Active Directory user does not have a job title this errors out because it will not load the property so rs.Propterties["title"] doesn't even exist to my knowledge.

Is there a cleaner way to do it than if (rs.Properties["title"].Count)

user.jobTitle = rs.Properties["title"][0].ToString();

I was looking into different operators like ?? and ?: but couldn't figure out how to get them to work properly.

rs.Properties is of type SearchResult from:

using System.DirectoryServices;
using System.DirectoryServices.ActiveDirectory;
using System.DirectoryServices.AccountManagement;

@PrestonGuillot rs is a SearchResult type. from the DirectoryServices. — James Wilson
– James Wilson, Commented Jun 11, 2013 at 22:23

Jon Skeet · Accepted Answer · 2013-06-11 22:23:07Z

How about:

user.jobTitle = (rs.Properties["title"].FirstOrDefault() ?? "").ToString();

That's assuming rs.Properties["title"] is of type IEnumerable<object> or something similar. If it's just IEnumerable, you'd need something like:

user.jobTitle = (rs.Properties["title"]
                   .Cast<object>()
                   .FirstOrDefault() ?? "").ToString();

The FirstOrDefault call will return null if the collection is empty.

(Now that we know the type of rs, it looks like the latter is required.)

You may want to wrap that into your own extension method, of course:

public static string GetFirstProperty(this SearchResult result,
                                      string propertyName,
                                      string defaultValue)
{
    return result.Properties[propertyName]
                 .Cast<object>()
                 .FirstOrDefault() ?? defaultValue).ToString();
}

nerdybeardo · Accepted Answer · 2013-06-12 23:05:09Z

2

Option 1

user.jobTitle = rs.Properties.Contains("Title") ? rs.Properties["Title"][0].ToString() : string.Empty;

Option 2

public static class SearchResultHelper
{
    public static string GetValue(this SearchResult searchResult, string propertyName)
    {
        return searchResult.Properties.Contains(propertyName) ? searchResult.Properties[propertyName][0].ToString() : string.Empty;
    }
}

Call would look like

user.JobTitle = rs.Properties.GetValue("Title")

Thanks to http://www.codeproject.com/KB/system/getuserfrmactdircsharp.aspx for AD example

edited Jun 12, 2013 at 23:05

answered Jun 11, 2013 at 22:28

nerdybeardo

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Comments

Timothy Shields · Accepted Answer · 2013-06-11 22:33:33Z

1

Is this what you're looking for?

user.jobTitle = rs.Properties["title"]
    .Cast<object>()
    .FirstOrDefault()
    .MaybePipe(x => x.ToString());

Helper function that I use everywhere:

public static TResult MaybePipe(this T obj, Func<T, TResult> func)
{
    return obj != null ? func(obj) : default(T);
}

edited Jun 11, 2013 at 22:33

answered Jun 11, 2013 at 22:22

Timothy Shields

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4 Comments

James Wilson Over a year ago

Sorry I forgot to include the type which is a SearchResult type. Which doesn't have the FirstOrDefault built in. Anyone to still do it?

Timothy Shields Over a year ago

@JamesWilson What is the type of Properties["title"]?

James Wilson Over a year ago

It is SearchResult, updated the original post as well. Jon Skeet was able to answer it similar to your suggestions.

Timothy Shields Over a year ago

@JamesWilson I added the Cast<object>() call which will turn your IEnumerable into IEnumerable<object>.

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