The Catch Block #88 - Mini C# Extension Methods

Welcome to the 88th edition of The Catch Block, and to 2022! Here's hoping this third edition of 2020 is better than the previous two.

In this edition, I show off a bit by showing some of my favorite mini-extension methods; that is, small methods that do just a tiny bit of functionality that I use often.

Plus: refactoring C# 10, resolutions, EF 6 to EF Core, and creativity powered by music. Let's get going!

Cool C# Mini-Extensions

I'm a big fan of writing extension methods in C# to make my code more readable, and to encapsulate functionality I'll be using quite a bit. For this first edition of 2022, I thought I'd share some of my favorite C# extensions that my team and I have been using in the last year.

Removing Last Instance of a Word in a String

Because I like to use Dapper a lot, I often have to construct complicated SQL queries, and many times I end up with extraneous operators at the end of the query. For example, one of my complicated queries might end with an extra AND that I need to remove.

I can do that with this tiny extension:

public static string RemoveLast(this string targetString, string removeToken)
{
    return targetString.Remove(targetString.LastIndexOf(removeToken));
}

An example implementation of this might look like this:

string sql = "SELECT * FROM tableName WHERE "

if(condition1 == true)
{
    sql += " ColumnName1 = @value1 AND ";
}
if(condition2 == true)
{
    sql += " ColumnName2 = @value2 AND ";
}

if(sql.Contains("AND"))
{
    sql = sql.RemoveLast("AND");
}

Note that this extension will remove the removeToken AND anything that follows it from the targetString.

Getting the End of the Day

Sometimes, for time range calculations, I really need to get the time "end" of a particular date. So, instead of getting January 2nd, 12:00:00 AM, I need to get January 1st, 11:59:59 PM. I can do that with this tiny extension:

public static DateTime EndOfDay(this DateTime date)
{
    return date.Date.AddDays(1).AddSeconds(-1);
}

Displaying a Nullable Boolean as Yes/No/NA

Since my team primarily works on internal business applications, we often have situations where we are using a boolean to represent a "yes or no" selection. So we coded up a tiny extension to display a nullable boolean as "yes", "no", or "N/A".

public static string AsYesNo(this bool? value)
{
    if (value.HasValue && value.Value == true)
        return "Yes";
    else if (value.HasValue && value.Value == false)
        return "No";
    else return "N/A";
}

We use this extension primarily on CSHTML views, like so:

<tr>
    <th>Is this a recurring issue?</th>
    <td>@Model.IsRecurringIssue.AsYesNo()</td>
</tr>